Counterweight tool

Abstract

A counterweight tool includes an attachment element, a lever arm, a counterweight element, a first locking mechanism, and a first crane connection point. The attachment element is arranged to be attachable to a component of a wind turbine. A lever arm is pivotally connected to the attachment element about a pivot point, the lever arm being pivotable between a first position, in which the lever arm is disposed at a first angle relative to the attachment element, and a second position, in which the lever arm is disposed at a second angle relative to the attachment element, the difference between the first angle and the second angle being greater than 25 degrees. A weight element is attached to the lever arm with a spacing from the pivot point, and a first locking mechanism is arranged to lock the position of the lever arm relative to the attachment element in a second position. The first crane connection point is arranged such that when the crane lifts the counterweight tool through the first crane connection point, the lever arm forms an angle of less than 30 degrees with the vertical direction, and when the attachment element is fixed in position relative to the crane, the lever arm forms an angle of less than 30 degrees with the vertical direction. Lifting or lowering the lever arm by the crane via a first crane connection point causes the lever arm to pivot about a pivot point from a first position to a second position.

Description

Technical Field

[0001] The present invention relates to a counterweight tool for use during construction and maintenance of wind turbines.

[0002] The term counterweight tool refers to a mechanical structure with a counterweight element attached to a lever arm that can be used to balance the weight of another component during lifting or other maintenance / construction operations. One application scenario for a counterweight tool is when lifting a mechanical component, where the position of the component to be lifted is such that the crane hook cannot be set directly above the component. In this case, the counterweight tool can be attached to the component, and then the crane hook can be attached to the counterweight tool so that the component can be lifted together with the counterweight tool.

[0003] Another application scenario of the balancing tool is during the installation of turbine blades on the rotor hub. Before all blades are installed, the rotor hub is unbalanced and difficult to drive it to rotate by the main shaft of the turbine. In this case, the balancing tool can be attached to one of the blade positions before the blades are installed. The balancing tool can then create a balance on the rotor, making it easier to turn the rotor to the correct position for installing the blades. Once the rotor has been turned to the correct position, the rotor can be locked in place and the balancing tool removed. Background Art

[0004] There are many examples of counterweight tools in the prior art. WO2020127478-A1, CN108190725-B and WO2022112250-A1 disclose some examples of counterweight tools for lifting components. However, in these applications, the components to be lifted are basically arranged below the counterweight tool, and there may be only a slight center of gravity offset.

[0005] An example of a weight tool for balancing a rotor during blade installation is disclosed in EP2650537-A1. In this case, the weight tool is provided with a joint so that the weight tool can be folded together to apply a small weight or unfolded so that it can apply a larger weight.

[0006] Although not directly relevant to the present invention, US8960747-B2 discloses an invention directed to a form of lifting yoke for a wind turbine component arranged to allow adjustment of the centre of gravity of a load so as to allow adjustment of the angle of the component when suspended from a crane.

[0007] Recently, there have been two developments in the field of wind turbine construction and maintenance that have had a significant impact on the methods and tools used in this field. The first is that the size of wind turbines has increased significantly, so all components have become heavier. For counterweight tools, this has increased the size of the counterweight elements required and thus also the lifting capacity required of the crane.

[0008] Secondly, rather than using a ground mounted crane, it is more common to use a self-elevating crane attached to or near the top of the wind turbine tower or a crane mounted at the nacelle. Since the crane must be lifted to the top of the wind turbine tower, it is undesirable to increase the size and strength (width) of the crane more than necessary. Therefore, it is very important to reduce the weight and size of the counterweight tool that needs to be lifted by the crane.

[0009] In this regard, it should be noted that the overall weight of the counterweight tool can be reduced by increasing its length to allow the counterweight element to be placed further away from the component to be lifted. However, this makes the tool larger and more cumbersome to lift. This generally requires a crane with a larger reach / size to prevent the tool from colliding with the nacelle or tower during lifting. Likewise, reducing the length of the counterweight tool reduces the size of the tool, but increases the required weight of the counterweight element. Since the crane must lift the combined weight of the component to be lifted and the counterweight tool, it is important to reduce the weight of the counterweight element.

[0010] Likewise, it is also desirable to reduce the complexity of counterweight tools. Therefore, it is important to provide tools that do not require any power source such as electrical or hydraulic power. Summary of the invention

[0011] Thus, a first aspect of the invention provides a counterweight tool that can be lifted via a self-lifting crane or a crane mounted at the nacelle.

[0012] A second aspect of the invention provides a counterweight implement that can be used to lift larger loads without requiring a larger crane.

[0013] A third aspect of the present invention provides a counterweight tool that does not require any onboard power source or powered actuators.

[0014] A fourth aspect of the present invention provides a weight balancing tool which is simple to use and robust.

[0015] These aspects are provided according to a counterweight tool as defined in claim 1. In this way, the counterweight tool can be lifted in its first position to the location of the component to be lifted. In the first position, the horizontal dimensions of the tool are very small and the lifting cables of the crane can be arranged very close to the base of the crane. Then, once the attachment element is attached to the component to be lifted, the lever arm can be deployed using only the lifting force from the crane, without any power source or powered actuator on the tool itself.

[0016] In this specification, the term "crane connection point" is to be understood as the point at which the line of action of the lifting force from the crane passes through the counterweight tool. Horizontally moving this point will cause the counterweight tool to assume different orientations in space. In the exemplary embodiments provided in the accompanying drawings, the crane connection point is a physical lifting ring or shackle to which the crane hook or lifting sling can be directly connected. Therefore, in an exemplary embodiment for a lifting application of the counterweight tool, there are two physically separated connection points for attaching the hook. However, within the scope of the present application, a displacement mechanism can be provided instead, wherein the horizontal position of the crane hook relative to the counterweight element can be adjusted by means of the displacement mechanism to change the position at which the line of action of the crane lifting force passes through the counterweight tool. An example of a displacement mechanism is an adjustable triangular cable arrangement, in which the length of the sides of the triangle can be adjusted to move the position of the hook. Therefore, a system with a displacement mechanism that can be placed in two separate positions will also be considered as a counterweight tool with a first and a second crane connection point.

[0017] It should also be noted that in the specification, reference is often made to a "hoisting cable of a crane". When the term "cable" is used, other forms of suitable flexible elongated structures such as ropes, wires, chains, slings, etc. should also be included in the meaning of the term, as will be clearly understood by a person skilled in the art.

[0018] In some embodiments, the component of the wind turbine to be lifted is a shaft with or without bearings, or a gearbox. The component may also be a rotor hub. In some embodiments, the attachment element is an attachment flange. In some embodiments, the attachment flange includes a bolt hole pattern that matches the bolt pattern on the component to be lifted.

[0019] In some embodiments, the difference between the first angle and the second angle is greater than 40 degrees, greater than 50 degrees, or greater than 60 degrees. In some embodiments, the difference between the angles is between 80 and 90 degrees. In some embodiments, when the crane is lifting the counterweight tool via the first crane connection point, the lever arm is at an angle of less than 20 degrees, less than 15 degrees, or less than 10 degrees from the vertical. In some embodiments, if the lever arm is curved or has another non-linear shape, then the "angle of the lever arm" can be defined by the angle between the pivot point and the connecting line between the center of gravity of the combined lever arm and the counterweight element.

[0020] In some embodiments, the lever arm further comprises a second crane connection point, the second crane connection point being fastened to the lever arm at a location between the attachment element and the first crane connection point, or to the attachment element.

[0021] In some embodiments, the distance between the attachment element and the first crane connection point is less than the distance between the counterweight element and the first crane connection point. In some embodiments, the first crane connection point is located at a point between the attachment element and the center of gravity of the counterweight element or at a point between the counterweight element and the center of gravity of the counterweight element.

[0022] In some embodiments, the distance between the attachment element and the first crane connection point is less than 35%, 30% or 25% of the length of the lever arm.

[0023] In some embodiments, the counterweight tool includes a plurality of removable counterweight elements. In this way, one or more counterweight elements can be added to increase the counterweight effect of the counterweight tool, or one or more counterweight elements can be removed to reduce the counterweight effect of the counterweight tool. This can be used to adjust the behavior of the counterweight tool to suit the part to be lifted.

[0024] In some embodiments, the connection between the lever arm and the attachment element is a pivotable hinge connection. In some embodiments, the pivotable hinge connection is detachable so that the lever arm can be detached from the attachment element. In this way, the attachment element can first be installed on the component, and then after the attachment element is installed, the lever arm and the counterweight element are lifted to the position of the attachment element and connected to the attachment element.

[0025] In some embodiments, the counterweight tool comprises an adjustment mechanism to allow adjustment of the horizontal position of the hoisting cable of the crane relative to the attachment element. In some embodiments, the adjustment mechanism comprises a flexible tensioning mechanism connected to the hoisting cable of the crane to enable displacement of the hoisting cable of the crane. In some embodiments, the adjustment mechanism comprises an adjustable cable arrangement to which the hoisting cable of the crane is attached.

[0026] In some embodiments, the weight tool further comprises a second locking mechanism for locking the position of the lever arm relative to the attachment element in the first position.

[0027] The present specification also discloses a method for transferring a component of a wind turbine from a nacelle of the wind turbine to the ground, using a counterweight tool as provided in the present specification. The method comprises the following steps:

[0028] a. attaching the crane hoist cable to the first crane connection point of the counterweight tool,

[0029] b. lifting the counterweight tool to the component in the nacelle,

[0030] c. attaching the attachment element of the counterweight tool to the component,

[0031] d. raising or lowering the lever arm of the counterweight tool via a crane until the lever arm is in its second position,

[0032] e. locking the lever arm in its second position,

[0033] f. moving the crane hoist cable to the second crane connection point of the counterweight tool, and

[0034] g. Lift the component and the counterweight tool and move them to the ground.

[0035] The present specification also discloses a method for transferring a component of a wind turbine from the ground to a nacelle of the wind turbine, using a counterweight tool as provided in the present specification. The method comprises the following steps:

[0036] h. attaching the component to an attachment element of the counterweight tool,

[0037] i. attaching a crane hoist cable to a second crane connection point of the counterweight tool,

[0038] j. lifting the component and the counterweight tool to the desired component position,

[0039] k. attaching the component to a nacelle of a wind turbine,

[0040] l. moving the crane hoist cable from the second crane connection point to the first crane connection point,

[0041] m. unlocking the lever arm from the attachment element,

[0042] n. lowering or raising the crane hook so that the lever arm pivots to its first position,

[0043] o. removing the attachment element from the component, and

[0044] p. Lower the counterweight tool to the ground.

[0045] It should be emphasized that when used in this specification, the terms "comprises / comprising / consisting of" are used to specify the presence of stated features, integer values, steps or components, but do not exclude the presence or addition of one or more other features, integer values, steps, components or combinations thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the accompanying drawings. It should be emphasized that the embodiments shown are only for illustrative purposes and should not be used to limit the scope of the present invention.

[0047] Figure 1 A perspective view of a top portion of a wind turbine tower and a counterweight tool of a first embodiment being lifted by a crane in a first position is shown, wherein a self-lifting crane is attached to the top of the nacelle, and.

[0048] Figure 2 Shows Figure 1 Side view of the arrangement.

[0049] Figure 3 Shows Figure 1 Side view of an arrangement in which a counterweight tool has been lifted and attached to a gearbox of a wind turbine.

[0050] Figure 4 Shown in Figure 3 Close-up view of the area delineated by circle IV.

[0051] Figure 5 Shows Figure 1 Side view of an arrangement in which the lever arm of the counterweight tool is pivoting from its first position to its second position.

[0052] Figure 6 Shown in Figure 5 Close-up view of the area demarcated by circle VI.

[0053] Figure 7 Shows Figure 1 Side view of an arrangement in which the lever arm of the counterweight tool has been locked in its second position.

[0054] Figure 8 Shown in Figure 7 Close-up view of the area delineated by circle VIII.

[0055] Fig. 9 Shows Figure 1 Side view of an arrangement in which the hoisting cables of the crane have been moved to a second lifting position on the counterweight tool.

[0056] Fig.10 Shown in Fig. 9 A close-up view of the area delineated by the circle X in FIG.

[0057] Fig.11 Shows Figure 1 Side view of the arrangement in which the crane has lifted the counterweight tool and attached gearbox out of the nacelle.

[0058] Fig.12 A schematic side view showing a first step of installing a counterweight tool according to a second embodiment on a component to be lifted.

[0059] Fig.13 Shows the installation Fig.12 The second step of the counterweight tool.

[0060] Fig.14 Shows the installation Fig.12 The third step of the counterweight tool.

[0061] Fig.15 Shows the components that have been installed Fig.12 The counterweight tool is prepared for lifting by a crane.

[0062] Fig.16 A schematic side view showing a first step of installing a third embodiment of a balancing weight tool on a rotor hub.

[0063] Fig.17 Shows the installation Fig.16 An intermediate step in the counterweight tooling.

[0064] Fig.18 The counterweight tool of the fourth embodiment is shown attached to a rotor and in its first position.

[0065] Fig.19 The second position is shown Fig.18 Weight tool. DETAILED DESCRIPTION

[0066] Figures 1 to 11 Different steps of a method for lifting a gearbox 1 of a wind turbine 2 using a nacelle-mounted crane 6 and a counterweight tool 8 according to a first embodiment of the invention are shown. In the figures, a method for transferring a gearbox from a nacelle 4 of a wind turbine to the ground is shown. However, similar procedural steps, run in reverse order, can also be used to transfer a gearbox from the ground to the nacelle. Although the counterweight tool 8 of the invention is shown for use with a nacelle-mounted self-elevating crane, it will be clear to a person skilled in the art that the counterweight tool of the invention can also be used with other forms of nacelle-mounted or tower-mounted cranes, as well as with different types of ground cranes.

[0067] It should be noted from the drawings that the gearbox in this exemplary embodiment of the wind turbine is mounted directly below the crane itself. Due to this location, the crane cannot directly lift the gearbox because the crane itself blocks access to the top of the gearbox. This is true for many situations where a self-lifting crane or other form of nacelle-mounted crane is used. In other types of wind turbines, the gearbox may be mounted further back in the nacelle. In these cases, it is possible for the nacelle-mounted crane to directly lift the gearbox and a counterweight tool would not be necessary. However, in most wind turbines, there will always be some form of component located below the crane itself. Therefore, a counterweight tool can be applied to many types of wind turbines.

[0068] It should also be noted that in the drawings a procedure is shown for lifting a gearbox, however, it should be clearly understood that a similar procedure can be used for lifting other components. An example is for replacing a main shaft with or without bearings. The invention should not be limited to a specific component, but should cover situations where it is applied to all relevant components.

[0069] As shown, the weight counterweight tool 8 has an attachment flange or attachment plate 10, a lever arm 12, and a weight counterweight element attached to one end of the lever arm in the form of a stack of weight counterweight plates 14. The lever arm 12 is pivotally connected to the attachment flange via a hinge joint 16, which is located at the other end of the lever arm opposite the end where the stack of weight counterweight plates is located. By comparison Figure 3 and Figure 7 It can be seen that the lever arm has two main positions, the lever arm being arranged substantially vertically ( Figure 3 ) is directed downwardly to a first position, and the lever arm is arranged to extend substantially horizontally from the attachment flange ( Figure 7 ) in a second position pointing outwardly.

[0070] In the first position, the counterweight tool has a smaller horizontal dimension, so that during the lifting of the tool to the nacelle, the counterweight tool can be arranged very close to the nacelle in the horizontal direction. This reduces the moment arm on the crane, because the crane hoisting cables 18 are closer to the base of the crane, thereby reducing the horizontal distance between the crane hoisting cables and the crane base. As known to those skilled in the art, the crane can lift a larger load when the crane hoisting cables are closer to the crane base than when the crane hoisting cables are farther away from the crane base.

[0071] Note that in this embodiment, the actual angle of the lever arm is about 5 degrees from vertical. While setting the lever arm completely vertical will minimize the horizontal size of the counterweight tool, in most cases the lever arm will not be completely vertical due to factors such as the arrangement of the lifting points, the geometry of the tool, and the weight of the various components of the tool.

[0072] In the second position, the counterweight element is located further away in the horizontal direction from the component to be lifted, thereby increasing the counterweight effect of the tool.

[0073] Reference now Figure 1-11 The procedure for lifting the gearbox from the nacelle to the ground is described in more detail.

[0074] In a first step, a crane hoist cable 18 is attached to a first crane connection point 20 on the counterweight tool. Details of the types of crane hoist cables, crane hooks, connection points, etc. are not provided here, as they are well known to those skilled in the art and may take different forms. In general, the present invention may be used with different types of connections between the crane and the counterweight tool, for example, slings, cables, chains, trunnions, lifting eyes, shackles, etc.

[0075] The crane then lifts the counterweight tool, such as Figure 1 and Figure 2 Due to the arrangement of the tool and the placement of the first crane connection point on the lever arm close to the attachment flange and away from the counterweight element, the lever arm will assume its first position in which the counterweight element pivots the lever arm downwards. The horizontal dimension of the counterweight tool is thus small, allowing the counterweight tool to be lifted close to and extending along the tower of a wind turbine without colliding with the tower.

[0076] like Figure 3 and Figure 4 As shown, when the counterweight tool has been lifted to the nacelle, the attachment flange is attached to the gearbox. It will be appreciated that the angle of the lever arm can be calculated because the geometry of the tool, the placement of the crane attachment point and the weight of the counterweight element are all known. The placement of the gearbox is also known, and the placement and orientation of the intended interface between the gearbox and the attachment flange are also known. Therefore, before starting the lifting operation, the position of the attachment flange relative to the lever arm is fixed in the desired direction. Therefore, when the counterweight tool reaches the gearbox, the attachment flange is ready to be directly attached to the gearbox. Although not shown in detail, a locking mechanism can be provided between the attachment flange and the lever arm to ensure the correct positioning of the attachment flange during the initial lifting operation.

[0077] Once the attachment flange has been attached to the gearbox, further lifting of the counterweight tool by crane will not displace the attachment flange further, as the attachment flange is now locked in place connected to the gearbox, while the gearbox remains locked in place relative to the nacelle. Figure 5 and Figure 6 As shown, as the crane is lifted further, the lever arm will therefore begin to pivot outwards. When the lever arm is in a horizontal position, the crane stops lifting and a locking pin 22 is inserted into flanges 24, 26 located on the attachment flange and on the lever arm, respectively, to lock the position of the lever arm relative to the attachment flange (and the gearbox). The flanges 24, 26 and the pin 22 can be considered as a form of locking mechanism, which locks the position of the lever arm relative to the attachment flange. A person skilled in the art of mechanical structure can provide other suitable forms of locking mechanisms.

[0078] Due to the arrangement of the pivotable connection between the lever arm and the attachment flange and the placement of the first crane connection point on the lever arm relative to the pivot point, the lever arm can be moved from the first position to the second position using only the lifting force of the crane. No hydraulic or electric power source or actuator is required on the counterweight tool itself. This greatly simplifies the counterweight tool and the installation procedure.

[0079] Once the lever arm is locked in place, the crane hoist cable 18 is released from the first crane connection point on the lever arm and moved to the second crane connection point 28. This brings the lifting point closer to the crane base, thereby also increasing the weight that the crane can lift. The second crane connection point is located at substantially the same horizontal position as the center of gravity of the combined counterweight tool and gearbox. Fig.11 As shown, the gearbox can now be removed from the nacelle and the gearbox is lifted out of the nacelle.

[0080] from Figure 9-11 It can be seen that in this embodiment, an additional cable 30 is connected between the crane hoist cable 18 and the third attachment point 32. By tensioning this additional cable 30, the horizontal position of the crane's lifting point relative to the counterweight tool can be fine-tuned. As the lifting position is adjusted, the angle of the counterweight tool relative to the nacelle can be fine-tuned. Counterweight plates can also be added or removed from the stack of counterweight plates 14 to adjust the counterweight tool to correctly match the actual component to be lifted.

[0081] In another embodiment (not shown), the angular position of the lever arm relative to the attachment flange can be locked in different positions to adjust the center of gravity of the combined counterweight tool and component. By tilting the lever arm more downward relative to the attachment flange, the counterweight effect of the counterweight element is reduced. In another embodiment (not shown), the position of the counterweight element on the lever arm can be adjusted rather than adding or removing counterweight plates from the stack of counterweight plates. Placing the counterweight element farther away from the attachment plate increases the counterweight effect of the counterweight tool, while placing the counterweight element closer to the attachment plate decreases the counterweight effect of the tool.

[0082] It should also be noted that the counterweight tool can be changed to fit different parts to be lifted by exchanging the attachment plate or flange with a different attachment plate or other form of attachment element. For example, when lifting the main shaft of a turbine, one type of attachment element can be provided, while when lifting a gearbox, another form of attachment element can be provided. Thus, the attachment element can be customized for different parts to be lifted while keeping the same lever arm and counterweight element.

[0083] Figure 12-15 A second embodiment of a counterweight tool 100 is shown, which also includes an attachment flange 102, a lever arm 104 and a counterweight element 106. This embodiment is very similar in function to the first embodiment and will not be described in detail. The main difference is that the attachment flange 102 and the lever arm 104 are separated from each other during the initial lifting operation. The attachment flange 102 is first lifted into position and attached to the component to be lifted 108 ( Fig.12 Once the attachment flange is in place, the combined lever arm 104 and weight element 106 are lifted to the attachment flange and connected to the attachment flange ( Fig.13 ), after the lever arm is pivoted into position ( Fig.14 ), the lever arm is locked in its second position ( Fig.15 ), as in the procedure of the first embodiment. The crane hoist cable 110 can then be moved from the first crane connection point 112 to the second crane connection point 114. The component to be lifted 108 and the counterweight tool 100 can then be lifted.

[0084] Figure 16-17A third embodiment of a counterweight tool 200 is shown. This embodiment is also similar in principle to the first embodiment, so it will not be described in detail. The main difference is that in this embodiment, the first crane connection point 202 is located close to the counterweight element 204 itself, and the crane lifting cable 206 thereby lifts the counterweight element from the tip of the lever arm 208. In this way, the lever arm in the first position is reversed relative to the orientation direction of the attachment flange 210. In the first position, the lever arm is therefore pointed upward in a direction away from the attachment plate. The lever arm remains substantially vertical during the process of being lifted into place, but the attachment flange is located at the bottom of the lever arm rather than the top during lifting. Therefore, the crane needs to lift most of the counterweight tool over the component 212 to be lifted. When the attachment flange reaches the component, the attachment flange is attached to the component. The crane can then lower the counterweight element instead of lifting it. Since the attachment flange is fixed to the component to be lifted, the operation of lowering the counterweight tool allows the lever arm to pivot outward and downward. When the lever arm is in a horizontal position, it is locked in place. The crane hoist cables may then be moved to the second crane connection point 214 and the combined components and tools may then be lifted as in other embodiments.

[0085] In the above description, a procedure for lifting a component to be lifted from the nacelle to the ground is described. However, a similar procedure can be performed in the reverse order to lift a component from the ground to the nacelle. In this case, the lever arm is placed in its second position relative to the attachment flange and locked in place. The attachment flange is then attached to the component to be lifted and the crane lifting cable is attached to the second crane connection point. The combined tool and component are then lifted to the nacelle. Once the component is fastened to the nacelle, the crane lifting cable is transferred to the first crane connection point, the locking mechanism is released and the crane lowers the lever arm, or according to other embodiments, lifts the lever arm to put the lever arm into its first position. The attachment flange can then be removed from the component and the counterweight tool is lowered to the ground.

[0086] Although the above description and drawings have shown the lever arm in a substantially horizontal position in the second position, it should be clear to those skilled in the art that the lever arm may also be arranged at an angle that is not completely horizontal in the second position.

[0087] Fig.18 and Fig.19An exemplary embodiment of a weighting tool 300 for assisting in rotating a rotor hub 302 during installation of blades 304 on the hub is shown. Typically, the blades are attached to the hub with the blades in a horizontal position. Therefore, the rotor hub needs to be rotated so that the blade mounting position is in a correctly positioned position for mounting the blades in a horizontal position. When one or two blades have been installed, it is difficult to rotate the rotor hub because the rotor hub is unbalanced. At this point, a weighting tool can be attached to the hub at a location without blades to provide more balance to the rotor hub, thereby making it easier to rotate the hub to a desired position.

[0088] In this embodiment, the blades 304 have been installed in a horizontal position and then the rotor hub has been rotated to place the blades 304 in a downward pointing position ( Fig.18 The weight tool 300 in its first position is then lifted and attached to the wheel hub ( Fig.18 ). The crane hoist cable 306 then further lifts the counterweight tool, causing the lever arm 308 to pivot upward. When the lever arm is in its second position, the lever arm is locked in place relative to the attachment flange 310 ( Fig.19 ). It should be noted that in this embodiment of the counterweight tool, only a single crane connection point 312 is provided, as the counterweight tool is not used to lift the rotor itself, but only to rotate it. Also, note that once locked in place on the hub, the hub can be rotated in an anti-clockwise direction (in the arrangement shown in the figure) using the crane by further lifting operations on the counterweight tool, and that once locked in place on the hub, the hub can be rotated in the opposite direction using the weight of the tool itself by lowering operations on the counterweight tool.

[0089] It should be noted that in this embodiment, the lever arm 308 itself is provided as an integrated lever arm and counterweight element, without providing a separately identifiable counterweight element. However, for the purposes of this specification, the tool of this embodiment still includes a lever arm and a counterweight element, it is just that the counterweight element is integrated into the beam of the lever arm itself.

[0090] It should be noted that the drawings and the above description have shown exemplary embodiments in a simple and schematic manner. Many specific mechanical details are not shown, because those skilled in the art should be familiar with these details, and if they are described in detail, they will only unnecessarily complicate the present description. For example, the specific materials used and their specific manufacturing procedures are not described in detail, because those skilled in the art will be able to find suitable materials and suitable processes to manufacture the counterweight tool according to the present invention.

Claims

1. A weight balancing tool, comprising: a. Attachment elements, b. Lever arm, c. Counterweight element, d. a first locking mechanism, and e. First crane connection point, f. the attachment element is arranged to be attachable to a component of a wind turbine, g. characterized in that the lever arm is pivotally connected to the attachment element about a pivot point, the lever arm is pivotable between a first position and a second position, in which the lever arm is arranged at a first angle relative to the attachment element, and in which the lever arm is arranged at a second angle relative to the attachment element, and the difference between the first angle and the second angle is greater than 25 degrees, h. The weight element is attached to the lever arm and has a spacing between the pivot point, i. the first locking mechanism is arranged to lock the position of the lever arm relative to the attachment element in the second position, j. The first crane connection point is located on either: i. a spacing between the lever arm and the pivot point, or ii. on the counterweight element, k. the first crane connection point is arranged so that, before attaching the attachment element to the component, when a crane lifts the counterweight tool or just the lever arm and the counterweight element by the first crane connection point, the lever arm is at an angle of less than 30 degrees to the vertical, and 1. wherein, when the attachment element is fixed in position relative to the crane and the attachment element is pivotably connected to the lever arm, lifting or lowering the lever arm via the first crane connection point by the crane causes the lever arm to pivot from the first position to the second position about the pivot point.

2. The weight balancing tool according to claim 1, characterized in that: The lever arm also includes a second crane connection point secured to the lever arm at a location between the attachment element and the first crane connection point.

3. The weight balancing tool according to claim 1 or 2, characterized in that: A distance between the attachment element and the first crane connection point is smaller than a distance between the counterweight element and the first crane connection point.

4. The weight balancing tool according to any one of claims 1 to 3, characterized in that: The distance between the attachment element and the first crane connection point is less than 35% of the length of the lever arm.

5. The weight balancing tool according to any one of claims 1 to 4, characterized in that: The weight tool includes a plurality of detachable weight elements.

6. The weight balancing tool according to any one of claims 1 to 5, characterized in that: The connection between the lever arm and the attachment element is a pivotable hinge connection.

7. The weight balancing tool according to any one of claims 1 to 6, characterized in that: The counterweight tool includes an adjustment mechanism to allow adjustment of the horizontal position of the hoisting cables of the crane relative to the attachment element.

8. The weight balancing tool according to any one of claims 1 to 7, characterized in that: The weight tool further includes a second locking mechanism for locking the position of the lever arm relative to the attachment element in the first position.

9. A method of transferring a component of a wind turbine from a nacelle of a wind turbine to the ground using a counterweight tool according to claim 2 or according to claim 2 and any one of claims 3 to 8, the method comprising the steps of: a. attaching a crane hoist cable to the first crane connection point of the counterweight tool, b. lifting the counterweight tool to the component, c. attaching the attachment element of the counterweight tool to the component, d. raising or lowering the lever arm of the counterweight tool via the crane until the lever arm is in its second position, e. locking the lever arm in the second position, f. moving the crane hoist cable to the second crane connection point of the counterweight tool, and g. Lift the component and the counterweight tool and move them to the ground.

10. A method of transferring a component of a wind turbine from the ground to a nacelle of a wind turbine using a counterweight tool according to claim 2 or according to claim 2 and any one of claims 3 to 8, the method comprising the following steps: a. attaching the component to an attachment element of the counterweight tool, b. attaching a crane hoist cable to the second crane connection point of the counterweight tool, c. lifting the component and the counterweight tool to the desired component position, d. attaching the component to the nacelle of the wind turbine, e. moving the crane hoist cable from the second crane connection point to the first crane connection point, f. unlocking the lever arm from the attachment element, g. lowering or lifting the lever arm via the crane so that the lever arm pivots to its first position, h. removing the attachment element from the component, and i. Lower the counterweight tool to the ground.

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