Wind turbine tower and carriage

Abstract

A wind turbine tower elevator carriage for clamping onto at least a first tower rail, the first tower rail extending upwardly of a wind turbine tower for releasably supporting the carriage thereon, the elevator carriage comprising a carriage body, a first releasable rail clamp and a second releasable rail clamp operable independently, and a lifting mechanism for raising and lowering the carriage body relative to the first releasable rail clamp.

Description

Technical Field

[0001] The present invention relates to a wind turbine assembly, a wind turbine tower elevator carriage, a method of assembling a wind turbine tower, and a wind turbine tower.

Background Art

[0002] There is a need for improved wind turbine assemblies, wind turbine towers, elevator carriages, and wind turbine assembly methods.

Summary of the Invention

[0003] According to a first aspect, a wind turbine tower elevator carriage for clamping onto at least a first tower rail, the first tower rail extending upwardly of a wind turbine tower for releasably supporting a carriage thereon, the elevator carriage comprising: a carriage body; independently operable first and second releasable rail clamps; a lifting mechanism for raising and lowering the carriage body relative to the first releasable rail clamp; is provided.

[0004] According to a second aspect, a method of assembling a wind turbine tower having a tower body and a rail extending upwardly of the tower body, the tower comprising a plurality of tower sections connected in series, each tower section having a respective tower body section and a respective rail section, the method comprising: erecting a first tower section; providing an elevator carriage on the rail of the first tower section; erecting a second tower section; providing an elevator carriage on the rail of the first tower section; Loading a second tower section onto the elevator carriage when the elevator carriage is in a first position, and transporting the second tower section by raising the elevator carriage above the rails to a second position, the second position being higher than the first position; transferring the second tower section onto the first tower section using the elevator carriage; connecting the second tower section to the first tower section; A method is provided that includes the above.

[0005] According to a third aspect, a wind turbine tower having a tower body and rails extending upward from the tower body, The rails have an outer surface S1 oriented away from the tower body and opposing side surfaces S2, S3, S4 connecting the outer surface S1 to the tower body. Each of the opposing side surfaces has a channel CH extending along the rail, and the channel includes a clamping surface S2 adjacent to a first support surface S3. The clamping surfaces S2 of the opposing side surfaces are parallel to a central plane CP extending outward from the tower body through the center of the width B of the base of the rail in the tower body. For each pair of opposing side surfaces, a first support surface S3 is inclined toward the clamping surface S2 and is angled by a first angle of 30° to 60° with respect to the central plane CP. A wind turbine tower is provided.

[0006] According to a fourth aspect, a wind turbine tower having a tower body and three or more rails extending upward from the tower body, The centers of adjacent rails are separated by at least 80° or at least 2 m of linear separation (e.g., at least 2 m of separation between the centers of adjacent rails) around the center of the tower body. A wind turbine tower is provided.

[0007] According to a fifth aspect, a wind turbine tower assembly a wind turbine tower, a fixed-level access platform, a variable-level access platform configured to form an access platform assembly that extends completely around the wind turbine tower, A wind turbine tower assembly is provided that includes.

[0008] The elevator carriage may include a nacelle support for supporting the wind turbine nacelle in a nacelle push-up position while the elevator carriage ascends the wind turbine tower.

[0009] The elevator carriage may include a carriage chassis, and the nacelle support may be pivotable relative to the carriage chassis about a substantially vertical axis when the elevator carriage is attached to the side of the wind turbine tower.

[0010] The nacelle support may be provided with a nacelle transfer mechanism for transferring the wind turbine nacelle from the nacelle push-up position to the top of the wind turbine tower.

[0011] The elevator carriage may include a tower section support for supporting the wind turbine tower section in a tower section push-up position while the elevator carriage ascends the wind turbine tower.

[0012] The tower section support may be provided with a tower section transfer mechanism for transferring the wind turbine tower section from the tower section push-up position to the top of the wind turbine tower.

[0013] Each releasable rail clamp, a rail clamp body, opposing rail clamp pads for clamping onto the rail, a pad actuator, and may include. The rail clamp pad is a wedge-shaped pad and has a first pad surface for contacting the rail and a second opposing pad surface that is received in a complementary-shaped shoe, and the second pad surface is not parallel to the first pad surface. The pad actuator is operable to move the wedge-shaped pad substantially parallel to the shoe and to the length of the rail.

[0014] The opposing rail clamp pads of the releasable rail clamp may each be a wedge-shaped pad and have a first pad surface for contacting the rail and a second opposing pad surface that is received in a complementary-shaped shoe, and the second pad surface is not parallel to the first pad surface. The pad actuator may be operable to move the opposing wedge-shaped pads substantially parallel to the shoe and to the length of the rail.

[0015] The rail clamp may include a clamp chassis having opposing clamp arms that support respective rail clamp pads, a clamp pivot actuator, and the clamp pivot actuator is operable to pivot the clamp arms relative to the opposing clamp arms between an open configuration and a closed configuration.

[0016] The clamp arms may be provided with a releasable self-locking linkage for holding the clamp arms in the clamped position.

[0017] The clamp pivot actuator may be operable to pivot the clamp arms relative to the clamp chassis between an open configuration and a closed configuration.

[0018] The clamp chassis may have a base for supporting against the bearing surface of the rail.

[0019] Each releasable rail clamp may comprise a repeated assembly of the rail clamp module.

[0020] The carriage body may be provided with a carriage sliding support for engaging a first tower rail extending upwardly from the wind turbine tower.

[0021] The elevator carriage may comprise a reaction arm (e.g., an articulated carriage arm) connected to the carriage body, and the reaction arm may comprise a lateral support assembly and a support arm actuator for engaging the lateral support assembly with the wind turbine tower.

[0022] The lateral support assembly may comprise a first support member for engaging an outer surface of the tower body of the wind turbine tower.

[0023] The lateral support assembly may comprise a second support member for engaging a second tower rail of the wind turbine tower.

[0024] The second support member may be configured to engage a side surface of the second tower rail proximate to the first tower rail.

[0025] The second support member may be configured to releasably receive the second tower rail within the second support member.

[0026] The reaction arm may comprise one or more extensible arm members for changing the separation between the carriage body and the lateral support assembly.

[0027] The elevator carriage may comprise opposing reaction arms (e.g., opposing articulated carriage arms).

[0028] The elevator carriage may comprise upper and lower main sliding supports.

[0029] Transferring the second tower section onto the first tower section may include sliding the second tower section to align it with the first tower section.

[0030] Transferring the second tower section onto the first tower section may include pivoting the second tower section to align it with the first tower section about a vertical axis.

[0031] The method may further include loading a wind turbine nacelle onto an elevator carriage at a third position, raising the elevator carriage to a fourth position, using the elevator carriage to transfer the nacelle to the top of a wind turbine tower, connecting the nacelle to the top of the wind turbine tower. The method may further include

[0032] Each of the opposing sides of the rail may further include a second bearing surface S4, and the clamping surface S2 is between the first bearing surface 3 and the second bearing surface S4. For each pair of opposing sides, the second bearing surface S4 is inclined toward the clamping surface S2 and is angled by a second angle of 30° to 60° with respect to the central plane CP.

[0033] The tower may include three or more rails extending upwardly from the tower, and the rails are spaced apart around the tower in a rotationally symmetric arrangement.

[0034] The centers of adjacent rails may be spaced apart by at least 80° around the center of the tower body. The centers of adjacent rails may be spaced apart by at least 90° around the center of the tower body.

[0035] The wind turbine tower may have three rails, and the centers of adjacent rails may be spaced 100° to 160° around the center of the tower body. The centers of adjacent rails may be spaced 110° to 140° around the center of the tower body.

[0036] The centers of the rails may be spaced around the center of the tower body in a rotationally symmetric arrangement.

[0037] The tower may include a tower body having an outer surface with a circular cross-sectional shape and rails protruding from the outer surface of the tower body.

[0038] Each rail may have an outer surface S1 oriented away from the tower body and opposing side surfaces S2, S3, S4 connecting the outer surface to the tower body. Each of the opposing side surfaces has a channel CH extending along the rail, and the channel includes a clamping surface S2 adjacent to the first support surface S3. The clamping surfaces S2 of the opposing side surfaces are parallel to a central plane (CP) extending outward from the tower body through the center of the width (B) of the base of the rail in the tower body. For each pair of opposing side surfaces, the first support surface S3 is inclined toward the clamping surface S2 and is angled by a first angle of 30° to 60° with respect to the central plane CP.

[0039] The rail or each rail may be hollow.

[0040] The rail or each rail may be braced between the clamping surfaces and include internal reinforcements extending upward from the tower.

[0041] The rail may be welded to the tower body along the length of the rail.

[0042] The tower may have a cylindrical tower body.

[0043] The tower body may include a plurality of tower body sections connected in series, and each rail may include a corresponding plurality of rail sections provided in each tower body section.

[0044] The wind turbine tower may have a tower body and a rail extending upward from the tower body. The wind turbine tower may have an elevator carriage, and the elevator carriage is configured to engage with the rail to raise and lower the elevator carriage upward along the wind turbine tower. The variable-level access platform may be configured to form a releasable connection with the elevator carriage to raise and lower the variable-level access platform.

[0045] The wind turbine tower may have a tower body and a rail extending upward from the tower body. The variable-level access platform may include a platform drive mechanism for engaging with the rail to raise and lower the variable-level access platform.

[0046] The variable-level access platform may be configured to be attached to the wind turbine tower, including releasably connecting the variable-level access platform to a fixed-level access platform.

Brief Description of the Drawings

[0047] Hereinafter, embodiments will be further described with reference to the accompanying drawings.

[0048]

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Mode for Carrying Out the Invention

[0049] In the examples described, similar features are identified by similar reference numerals, but in some cases have one or more of an increment of 100 times, a subscript, and a typographic mark (e.g., prime). For example, in different figures, 120, 120’, 120’’ and 120’’’ are used to indicate the wind turbine tower rails.

[0050] This application describes an improved method for assembling a wind turbine and related components used therein.

[0051] FIG. 1 shows a partially assembled wind turbine assembly 100 during assembly. A wind turbine tower 110 is shown, on which an elevator carriage 140 is mounted, and the elevator carriage supports a rotor-nacelle assembly 170 and is ready to lift the rotor-nacelle assembly to the top of the tower. The illustrated wind turbine assembly 100 also has an optional fixed-level access platform 112, for example, to provide access to an access portal (e.g., a hatch) into the interior of the wind turbine tower 110, for example, for an operator to access during assembly, inspection, and maintenance, which can be used in an offshore wind turbine assembly and can be omitted from an onshore wind turbine assembly.

[0052] The illustrated wind turbine assembly 100 has a floating foundation 114 fixed to the seabed, for example, a PelaStar (trademark) tension leg platform (TLP). However, this wind turbine assembly is not limited to a floating foundation. For example, the wind turbine may alternatively be mounted on an onshore or offshore hard standing, or on an alternative buoyancy foundation.

[0053] The tower 110 has a tower body 116 having (one or more) tower rails 120 extending upwardly outside the tower body. The rail(s) 120 extend along the length of the tower 110 (the vertical direction of the upright tower). For example, the rail(s) may extend along substantially the entire length of the tower (the length above the base or, in the case of an offshore wind turbine, as a percentage of the length of the tower above the sea surface), or at least 90% of the length of the tower, or at least 75% of the length of the tower, or at least 40% of the length of the tower. The tower body 116 may be hollow, for example, substantially cylindrical. For example, if the tower body has a tower body where only a portion of the tower is cylindrical, the one or more rails may extend substantially along the length of the cylindrical portion of the tower body, or at least 90% of the length of the cylindrical portion of the tower body.

[0054] When the tower 110 has a plurality of tower rails 120, the rails are widely spaced around the outside of the tower body 116. The centers of adjacent rails 120 are spaced apart by at least 80° (e.g., at least 90°) or at least 2 m of linear separation around the center of the tower body. The tower body can have a diameter (or horizontal width) of at least 2.3 m. By being widely spaced, it is possible to apply a substantial horizontal torque to the adjacent rails without damaging the tower body 116. As shown in FIG. 1, three rails 120 can be provided. With respect to the central axis of the tower body 116, in the wind turbine assembly 100 of FIG. 1, the centers of the three rails 120 are in a substantially rotationally symmetric arrangement, spaced apart at 120° intervals (e.g., a three-fold rotationally symmetric arrangement), and are substantially equally spaced around the tower body 116.

[0055] FIG. 2A shows the arrangement of the rails 120 in a perspective view of a cutaway section of the tower 110, and FIG. 2B shows the arrangement of the rails in a view looking down the cutaway tower axially (e.g., a vertical view of an upright tower). FIG. 2C shows a cross-sectional view of the tower 110 having a corresponding arrangement of the rails 120' of a second design, as will be further described in relation to FIG. 3B.

[0056] The rails 120 are connected to the tower body 116 along their lengths. For example, each rail is continuously welded to the tower body along the length of the rail, or in the case of a multi-section tower, each rail section is welded to its respective tower body section along the length of the rail. Alternatively, using connection parts such as bolts, rivets or screws, each rail can be connected to the tower body along the length of the rail, or in the case of a multi-section tower, each rail section can be connected to its respective tower body section along the length of the rail.

[0057] The arrangement of the rails 120 around the tower body 116 provides a track for the elevator carriage 140 to travel along and provides structural reinforcement of the tower body against lateral forces and torques both during assembly and during use of the wind turbine assembly. The lateral forces acting on the tower 110 and the lateral vibrations of the tower result from the influence of the wind on the wind turbine assembly and tower during use. Additionally, during self-assembly, as shown in FIG. 1, when the elevator carriage 140 is used outside the tower body 116, particularly when supporting the rotor nacelle assembly 170, large forces are generated. Reinforcement of the tower body 116 by the arrangement of the reinforcement rails 120 spaced apart (by at least 80° or at least 2 m) around the tower body enables the construction of the tower 110 with lower requirements for the strength of the tower body and enables the tower body to have a lower mass than otherwise required (and may also enable the tower body to be narrower than otherwise required). The tower body may be formed from steel having a maximum thickness of 100 mm. The tower body may have a minimum thickness of 12 mm.

[0058] In FIGS. 1 to 2C, the tower rails 120 are arranged in a rotationally symmetric arrangement (at 120° intervals) around the tower body 116. Alternatively, the rails may be offset from the rotationally symmetric arrangement to a limited extent. In the case of three rails, for the first rail, the centers of the second and third rails may be offset by up to 20° or up to 10° from the rotationally symmetric arrangement (with respect to the first rail). FIG. 2D shows an exemplary alternative arrangement of three rails 120' in which the centers of the second and third rails are 100° apart from the first rail around the center of the tower body 116.

[0059] The rails 120 disposed around the tower body 116 in a rotationally symmetric arrangement resist lateral forces and provide structural reinforcement of the tower body with low complexity (e.g., maintaining a vibration response that is generally rotationally symmetric) to control the vibration mode. However, as described, by being offset from the rotationally symmetric arrangement to a limited extent, it becomes possible to provide a larger gap between two adjacent rails than in the case of a completely rotationally symmetric arrangement, facilitating the provision of an access opening (e.g., a hatch) to the tower body 116 for an operator to enter the tower body 116 during assembly, maintenance, and disassembly. As described, being offset from the rotationally symmetric arrangement to a limited extent reduces the structural reinforcement by the rails and the mode control of the tower to a slight extent compared to the rotationally symmetric arrangement.

[0060] Figures 1 - 2D relate to a wind turbine tower having three rails. In a further alternative arrangement, four rails spaced apart around the tower (e.g., on a tower having a circular or square cross-sectional shape) can be provided at 90° intervals (or offset from the rotationally symmetric arrangement by up to 20° or up to 10°, e.g., spaced around the tower at intervals of at least 80°).

[0061] Each of the plurality of rails 120 can be substantially identical and connected to the underlying tower body 116 in a substantially similar manner. The use of substantially identical rails 120 allows each rail to provide substantially the same structural reinforcement to the underlying tower body 116.

[0062] Providing a plurality of rails 120 extending upwardly along the tower 110 can enable the elevator carriage 140 to be mounted on the tower at different angular positions around the tower. For example, in the case of an offshore wind turbine tower 110, the elevator carriage 140 can be mounted at an angular position around the tower 110 that is most favorable for the prevailing conditions of wind, waves, and currents. Alternatively, the elevator carriage 140 can be mounted at the same position on the tower 110 (on the same tower rail) in each case.

[0063] In the illustrated tower 110, the tower body 116 has an outer portion with a substantially circular cross-section, as shown in FIGS. 1-2D. However, the tower body may alternatively have a non-circular shape having a cross-sectional shape, for example, a substantially triangular, square, or other polygonal shape (e.g., hexagonal).

[0064] FIG. 3A shows a cross-sectional view through a rail 120 perpendicular to the length of the rail corresponding to the rails shown in FIGS. 1-2B.

[0065] The sides of the rail or each rail 120 merge with the tower body 116 at the base of the rail, and the (outer) sides of the rail are spaced apart by a base width B, which enables the rail to resist lateral (e.g., circumferential) forces.

[0066] One or more rails 120 may be hollow. The rail may be formed from a sheet material, such as sheet steel (e.g., at least 6 mm thick). For example, the rail 120 shown in FIG. 3A can be formed by bending from a single sheet of material, or by welding sheets of material together, or by a combination of bending and welding. Inclusion of a bend 126 between the faces of the rail 120 (extending along the rail) increases the strength of the rail to resist buckling in use (e.g., the strength to resist forces perpendicular to the length of the rail).

[0067] The rail may be formed from a material having sheet thicknesses T1, T2 of less than 20% of the width W of the rail (H indicates the height of the rail, which is the radial extension of the rail from the tower body, and the width W is perpendicular to the height H).

[0068] Being hollow allows the rail 120 to provide structural reinforcement for the tower body 116 with a much lower mass than in the case of a solid rail of corresponding size (in particular, formed from a sheet material having thicknesses T1, T2 that are much smaller than the width W of the rail). As explained, the combination of spaced hollow rails 120 around the tower body 116 allows the tower 110 to be constructed with higher strength than a corresponding tower having the same mass but solid rails.

[0069] The rail 120 of FIG. 3A has an outer surface S1 facing away from the tower body 116 and opposing side surfaces each having a clamping surface S2 between a first side bearing surface (first sliding groove) S3 and a second side bearing surface (second sliding groove) S4.

[0070] For each side surface of the rail 120, the clamping surface S2 and the first and second side bearing surfaces S3, S4 have a concave configuration forming a channel CH extending along the length of the rail. Providing separate clamping surface S2 and bearing surfaces S1, S3, S4 allows the clamping action to be provided without the risk of damaging the bearing surface and interfering with the sliding bearing action.

[0071] Forming the side surface of the rail from a plurality of adjacent surfaces (e.g., S2, S3, S4) angled with respect to each other provides a strengthening effect to support the structure of each rail and allows for the use of thinner and lighter sidewalls for the tower rails.

[0072] The opposing clamping surfaces S2 may be substantially parallel to each other (as shown in FIG. 3A). The opposing clamping surfaces S2 may extend outwardly (e.g., extend perpendicular to the lower tower body and, for example, radially with respect to the center of the tower body) through the center of the width B of the base of the rail 120 from the tower body 116, as shown in FIG. 3A, and may extend substantially parallel to a central plane CP. The rail 120 may be substantially mirror-symmetric with respect to the central plane CP.

[0073] In use, with the elevator carriage 140 mounted on one or more rails 120, a clamp mechanism (releasable rail clamp) of the elevator carriage clamps on the opposing clamp surface S2 to support the weight of the elevator carriage and any load it carries. The load support force results from the static friction between the clamp mechanism and the rail(s), and the shear force resulting from any mechanical deformation of the clamp surface, which can be collectively referred to as the "traction force". As shown in FIG. 3A, when the opposing clamp surfaces S2 are substantially parallel, the clamp mechanism enables clamping substantially on the clamp surface without decomposing the clamping force so as to be directed towards or away from the tower body 116, enhancing the stability of the elevator carriage 140 on the tower 110.

[0074] Alternatively, the opposing clamp surfaces S2' may flare out from each other, as shown in FIG. 3F. The opposing clamp surfaces S2' extend outwardly (e.g., perpendicular to the underlying tower body, e.g., radially with respect to the center of the tower body) through the center of the width B of the base of the rail 120 from the tower body 116, as shown in FIG. 3F, and may be angled θ away from parallel with respect to a central plane CP. The clamp surfaces S2' may be angled θ up to +25° (e.g., up to 15° or up to 10°) or up to -25° (e.g., up to -15° or up to -10°) with respect to the central plane CP. Even when the clamp surfaces S2' are not parallel to the central plane CP, the clamp surfaces S2' are angled at least 5° with respect to the adjacent side support surfaces S3, S4. The bend 126' provided by the clamp surfaces S2' angled away from parallel with the adjacent side support surfaces S3, S4 increases the strength of the rail to resist buckling during use.

[0075] When the clamp surfaces S2' flare out away from the tower body 116, the clamping force of the clamp mechanism decomposes to bias the elevator carriage 140 towards the tower 110.

[0076] The outer surface S1 may be perpendicular to a central plane CP that extends outward from the tower body 116 through the center of the width B of the base of the rail 120 (e.g., perpendicular to the lower tower body, e.g., extending radially with respect to the center of the tower body).

[0077] In use, the elevator carriage 140 is attached to one or more tower rails 120 (e.g., the first tower rails 120A, 120A' as shown in FIGS. 5A - 5E), and at least the chassis support assembly of the chassis 142 of the elevator carriage supports against at least the first tower rail. One or more lateral support assemblies of the elevator carriage 140 also support against both side surfaces of the second tower rail or against only one side surface of the second tower rail, either in a manner similar to the chassis support assembly as shown in FIG. 5A or as shown in FIG. 5E, respectively, and can support against the second tower rails (120B, 120B').

[0078] In at least the first tower rail 120A, each support assembly supports against each of the first side support surfaces S3. The support assembly may also support against the second side support surface S4 to provide a four - sided support effect, or the support assembly may also support against the outer surface S1 to provide a three - sided support effect (or in a further alternative, the support assembly can support against both the second side support surface S4 and the outer surface S1). When the support assembly supports against the outer surface S1, the support assembly is configured to support against the region of the outer surface S1 adjacent to its edge (adjacent to the first side support surface S3), where the outer surface S1 may be stronger, and not support against the central region of the outer surface S1, where the outer surface S1 may not be as strong. The three - or four - sided support effect provides effective transmission of forces in any direction from the carriage to the rail 120.

[0079] When the support assembly supports against the first side support surface S3 and the second side support surface S4, the support assembly provides a strong four-sided support action. The four-sided support action enables the support portion and the rail to substantially equally resist forces in any direction perpendicular to the length of the rail. On each side, the illustrated first support surface S3 is angled approximately 45° with respect to the central plane CP (e.g., also approximately 45° with respect to the outer surface S1). Alternatively, the first support surface S3 may be angled 30° - 60° with respect to the central plane CP. Providing the second side support surface S4 provides a wider base adjacent to the tower body 116 to the rail 120, which can enhance the dispersion of forces and torques from the rail to the tower body 116.

[0080] The hollow rail may additionally be provided with transverse internal reinforcements (extending, for example, substantially circumferentially with respect to the tower body 116, in a direction transverse to the radial direction of the tower body and perpendicular to the length of the rail). Providing the internal reinforcements can increase the strength of the rail, for example, to resist the clamping force of the elevator carriage. Providing the internal reinforcements may make it possible to form the rail with less mass than a corresponding rail of the same strength without internal reinforcements.

[0081] As shown in FIG. 3B, the hollow rail 120’ may be provided with an internal reinforcement 122 extending between the opposing clamping surfaces S2. The internal reinforcement 122 extending between the clamping surfaces S2 of the rail 120’ (e.g., opposing clamping surfaces or other clamping surfaces) withstands well the clamping force from the clamping mechanism of the elevator carriage 140 during use and also withstands well the lateral forces from supporting the elevator carriage (e.g., the torque generated from the elevator carriage supporting a load, as well as the exposure of the elevator carriage and any load to wind), thereby increasing the strength of the rail.

[0082] As shown in FIG. 3B, the internal reinforcement may be formed of a material having the same thickness T3 as at least the thickness T2 of the side surface of the rail 120'. Alternatively, as shown in FIG. 3C, the internal reinforcement 122' may be formed of a material having a thickness T3 that is thinner than the thickness T2 of the side surface of the rail 120''. The use of the thinner T3 internal reinforcement 122' makes it possible to form a lightweight rail 120''.

[0083] As shown in FIG. 3B, the outer surface S1 may be formed of a material having the same thickness T1 as at least the thickness T2 of the side surface (at least the clamping surface S2) of the rail 120'. Alternatively, as shown in FIG. 3C, the outer surface S1' may be formed of a material having a thickness T1 that is thicker than the thickness T2 of the side surface of the rail 120''. Using the thicker T1 material for the outer surface S1' makes it possible to form the rail 120'' with a thinner side surface of thickness T2 and to form a lightweight rail.

[0084] Each of the outer surface S1 and the side walls (the clamping surface S2, the first support surface S3, and the second support surface S4 if present) may have a thickness T1, T2 of at least 12 mm.

[0085] When the support assembly supports against the first side support surface S3 and the outer surface S1, the support assembly provides a strong three-sided support action. In the case of the three-sided support action, as shown in FIG. 3D, the rail 120''' can omit the second side support surface S4 and again form a channel CH along the side surface of the rail 120'''.

[0086] The rail 120''' can have a width W''' of the outer surface S1 that is significantly larger than the height H''' (e.g., at least 50% larger), which can enhance the dispersion of forces and torques from the rail to the tower body 116.

[0087] As shown in FIG. 3D, the hollow rail 120’’’ may be provided with (additionally or alternatively) diagonal internal reinforcements 122’’’ extending between the side surface of the rail and the outer surface S1’’’, which enhance the strength of the rail to withstand the clamping force from the clamping mechanism and the lateral forces (e.g., the supporting force from the supporting assembly of the elevator carriage 140) from the elevator carriage 140 during use.

[0088] The transverse internal reinforcements 122, 122’ in FIGS. 3B and 3C may be provided, additionally or alternatively, on the diagonal internal reinforcement 122’’’ in FIG. 3D. The diagonal internal reinforcement 122’’’ in FIG. 3D may be provided, additionally or alternatively, on the transverse internal reinforcements 122, 122’ in FIG. 3B as shown by the optional internal reinforcement 122’’ shown in dashed lines in FIG. 3C, which enhances the strength of the rail 120’’ to withstand the clamping force on the surfaces S1’ and S3 and resist the bending of the rail under lateral forces.

[0089] The rail and the tower body may be painted or coated (e.g., with a zinc coating) to protect against corrosion. However, during use, the clamping mechanism applies a strong force to the clamping surface S2 of the rail, which may damage the paint on the painted rail and lead to corrosion if it is not repainted after use.

[0090] As shown in FIG. 3E, each clamping surface S2 of each rail may be provided with a corrosion-resistant reinforcement strip 124 extending along the length of the rail. The reinforcement strip 124 may be formed of stainless steel, weather-resistant steel (e.g., COR-TEN (registered trademark) steel), or a high-strength polymer. By providing the corrosion-resistant reinforcement strip 124, the clamping surface S2 is protected during use without the need to repaint to protect against corrosion after use.

[0091] The described rail enables the elevator carriage 140 to be firmly connected to one or more of the rails by a three-sided or four-sided sliding support action and a weight-supporting clamping mechanism.

[0092] The elevator carriage 140 is releasably connected at least on the first tower rail 120A (for example, the carriage chassis 142 is connected on the first tower rail), has one or more carriage arms 146 (for example, one or more articulated carriage arms), and in particular provides lateral stability (substantially horizontal during use) to the elevator carriage to resist the force of the wind on the elevator carriage and any load carried by the elevator carriage (for example, the carriage arm, as a reaction arm, enables reaction to such forces).

[0093] The elevator carriage 140 can be releasably connected on two or three rails using one or more carriage arms 146 each having a support assembly that receives the respective second tower rails 120B, 120B, enabling the carriage arm to support against the second tower rail.

[0094] Alternatively, one or more carriage arms 146 of the elevator carriage 140 may support against the outside of the tower body 116 and either or both of the one or two second tower rails 120B, 120B'.

[0095] If the elevator carriage is releasably connected to only one rail during use, as shown in the cross-sectional view of FIG. 4, the tower 110'''' may be provided with only a single rail 120'.

[0096] Figure 5A shows the carriage chassis 142 of an elevator carriage 140 connected to tower 110. As shown, the carriage chassis 142 has a carriage body 144 that releasably engages on a first tower rail 120A and has one or more carriage arms 146 (e.g., a pair of carriage arms 146) that extend from the carriage body and engage a second tower rail 120B. The carriage arms 146 may be extendable to enable the carriage arms to engage the second rail 120B at different heights above the tapered tower body 116 of the wind turbine tower 110 or to enable use of the elevator carriage on towers that have rails of different sizes or different spacings. By engaging the second tower rail 120B, the carriage arm(s) 146 enable the carriage chassis 142 to resist lateral forces (generally horizontal forces) including wind forces acting on both the elevator carriage 140 and any carried load.

[0097] As shown in FIG. 5A, the carriage chassis 142 may have a pair of opposing carriage arms 146. Alternatively, the carriage chassis may have only one carriage arm (not shown). In a further alternative, the carriage chassis 144’ can have three or more carriage arms 146 having, for example, upper and lower pairs of carriage arms as shown in FIG. 5B. Using two or more pairs of carriage arms 146 enables the elevator carriage 140 to resist lateral forces received by a larger load (e.g., a larger tower section and a larger rotor-nacelle assembly) and to distribute the forces over a wider area of the tower 116.

[0098] In each of FIGS. 5A and 5B, on the carriage chassis 142, 142', there are provided a support assembly 150 (e.g., a sliding support for releasably engaging with the rail and sliding along the rail when in use) for stabilizing the carriage chassis on the first tower rail 120A and at least one second tower rail 120B, and a clamping mechanism 160 for supporting the carriage chassis on the first rail 120A. The support assembly and the clamping mechanism can be integrated into a composite support clamping unit 151 (150, 160 as shown in FIGS. 5C and 7A) that provides both functions. In the configurations of FIGS. 5A and 5B, the support assemblies 150 (and optionally the clamping mechanisms 160) provided on each carriage arm 146 releasably hold each second tower rail 120B within their respective support assemblies (e.g., they extend around both side surfaces of each second tower rail and enable an opposing clamping action on each second tower rail, similar to a hand gripping with opposing thumb and fingers, e.g., clamping in the opposing channels CN on the side surfaces of each tower rail).

[0099] FIG. 5C shows a further carriage chassis 142'' of the elevator carriage before releasable connection to the tower. FIGS. 5D and 5E show the carriage chassis 142'' releasably connected on the tower 110 in their respective first and second configurations.

[0100] The carriage chassis 142'' has a composite support clamping unit 151 (or alternatively, separate support assembly 150 and clamping mechanism 160) with a support assembly and a clamping mechanism for engaging with the first tower rail 120A. The carriage chassis 142'' has one or more carriage arms 146 that extend from the carriage body and are provided with further support portions 150B'' to resist lateral forces on the carriage chassis 142''.

[0101] Figure 5D shows a carriage chassis 142'' connected to a tower in a first configuration, where a composite support clamp unit 151 is connected to a first tower rail 120A', and a further support portion 150B'' is engaged with the tower body 116. Each of the further support portions 150B'' is provided with a first support member 148A for engaging with the tower body 116. For example, the first support member 148A may be a support pad or a roller. When the first support member 148A is a roller, it may be spherical to allow rolling in different directions, or may be shaped to complement the shape of the tower body, for example, substantially cylindrical. The first support member 148A may be used to resist lateral forces on the carriage chassis 142'' when the second tower rail 120B' is beyond the reach of the carriage arm 146'', for example, in the lower portion of the tapered tower body 116, or when the carriage chassis is attached to the tower body without the second tower rail 120B'.

[0102] Figure 5E shows a carriage chassis 142'' connected to a tower in a second configuration, where a composite support clamp unit 151 is connected to a first tower rail 120A', and a further support portion 150B'' is engaged with a second tower rail 120B'. Each of the further support portions 150B'' is provided with a second support member 148B for engaging with the second tower rail 120B' by an extension of the carriage arm 146'' (for example, with a channel within the side surface of the second tower rail). For example, the second support member 148B may be a support pad or a roller. When the second support member 148B is a roller, it may be spherical to allow rolling in different directions, or may be shaped to complement the channel CH of each tower rail. The second support member 148B may be used to resist lateral forces on the carriage chassis 142'' when engaged with the second tower rail 120B' and, for example, the upper portion of the tapered tower body 116 having the second tower rail 120B'.

[0103] Each of the further support portions 150B'' of the carriage chassis 142'' shown in FIGS. 5C to 5E is provided with both a first support member 148A for engaging (e.g., biasing) with respect to the tower body 116 and a second support member 148B for engaging with respect to the second tower rail 120B. However, alternatively, for further support, only the first support member 148A or the second support member 148B may be provided (e.g., only a spherical or substantially cylindrical roller that can engage with either the tower body 116 or the second tower rail 120B' can be provided).

[0104] As shown in FIG. 5C, the elevator carriage 140 has a load support portion connected to the chassis body 144 by a lateral pivoting mechanism 145 (e.g., enabling pivoting of the load support portion about a substantially vertical axis during use). When used to carry a load, the lateral pivoting mechanism 145 is stabilized by a carriage arm 146 that abuts against the second tower rails 120B, 120C as shown in FIG. 5E or against the outside of the tower body 116 as shown in FIG. 5D during use, enabling the load to pivot with respect to the chassis body 144. The pivoting of the load with respect to the chassis body 144 allows the lateral torque on the elevator carriage 140 and the load (e.g., the rotor-nacelle assembly 170 or the tower section 110' as shown in FIGS. 9C to 10C) from the wind force not to concentrate only on the tower rail 120 (e.g., the first tower rail 120A) to which the carriage body is attached, but to be stabilized by a reaction torque that spreads around the tower body 116 by the carriage arm 146.

[0105] FIG. 5F shows a side view of an elevator carriage 140 that is clamped onto an upright tower section 110A' and further transports a tower section 110B' on a tower section platform 182 of a carriage adapter 180, which is further described in relation to FIGS. 9A-9L. The carriage adapter 180 is connected to the elevator carriage 140 by a carriage linkage 140L.

[0106] FIG. 5G shows a perspective view of the elevator carriage 140 of FIG. 5F. The elevator carriage 140 has a carriage body 144 having a composite support clamp unit 151 for releasably clamping onto a first rail 120A of a wind turbine tower 110, and a carriage arm 146 provided with a further support portion 150B'' for resisting lateral forces and supporting a support member 148A (e.g., a roller). The carriage body 144 is provided with a sliding support pad 140B for engaging an outer surface S1 of the first rail 120A. The elevator carriage 140 may be provided with a carriage access platform 140P.

[0107] Figures 6A - 6E show a support assembly 150 that releasably engages with a rail 120 during use and slides along the rail. The support assembly 150 has a first sliding support surface 152 that engages with a first side support surface S3 of the rail 120, and a second sliding support surface 154 that engages with a second side support surface S4 of the rail. Each sliding support surface 152, 154 can be configured to engage with the surfaces S3, S4 that are under the rail during use. For example, one or more hydraulically actuated support surface pistons 156 are provided. The hydraulically actuated engagement mechanism 156 (e.g., a piston) may be covered by a protective cover 157 as shown in FIG. 6B. The support assembly 150 is provided with a pivotable release linkage 158 that can be actuated by a hydraulic closure piston 159. The pivotable linkage 158 allows the support assembly 150 to open and be received onto the rail 120 and then close around the rail with a small clearance, enabling the support assembly to slide along the rail without disengaging from the rail. The (optional) hydraulically actuated support surface piston 156 (or other hydraulically actuated engagement mechanism) may operate to grip the rail 120 for additional stabilization when the support assembly 150 is not sliding along the rail.

[0108] Alternatively, the support assembly and the clamping mechanism may be integrated into a composite support clamp unit 151 that provides both functions. FIGS. 7A - 7G show the composite support clamp unit 151. The composite support clamp unit 151 has opposing articulated self - locking arms 162 (clamp arms configured to hold the clamp arms in a clamped position during use) that support clamp pads 164, 164.

[0109] FIGS. 7A and 7G show the composite support clamp unit 151 in a fully open configuration where both self - locking arms 162 are widely open to allow the clamping mechanism to engage with (or disengage from) the rail 120'.

[0110] Figures 7B, 7C, and 7D show the composite support clamp unit 151 closed around the rail 120' in a closed configuration, in which the self-lock arm 162 is in a state where the clamp pad 164 is loosely contacting or approaching the clamp surface S2 of the rail, with the clamp pad protruding into the channel CH, and is closed in the self-lock position, and the composite support clamp unit is held on the rail.

[0111] Figures 7E and 7F show the composite support clamp unit 151 in a closed and locked configuration with the clamp pad 164 firmly clamped on the rail 120'. The composite support clamp unit 151 is firmly clamped on the rail 120' by a hydraulic mechanism 168. In the illustrated composite support clamp unit 151, the clamp pad 164 is wedge-shaped and slidable within a shoe 166 of complementary shape. By the operation of the hydraulic clamp mechanism 168, the wedge-shaped clamp pad 164 is slid along the shoe (proximally in the length direction of the rail 120'), wedging the wedge-shaped clamp pad firmly against the rail and firmly and releasably clamping the composite support clamp unit 151 on the rail. The wedge-shaped arrangement of the clamp pad 164, which is slidable relative to a shoe of complementary shape held rigidly within the composite support clamp unit 151 (e.g., by a self-lock arm or an alternative rigid mechanism), enables the rail 120 to be clamped sufficiently firmly, and the resulting traction force (shearing forces resulting from static friction and any mechanical deformation of the surface) enables the clamp mechanism to support a very high mass. For example, each composite support clamp unit 151 can support at least 10 tons (e.g., at least 30 tons) of mass in a fully clamped position on a substantially vertical rail.

[0112] The composite support clamp unit 151 is shown in FIG. 7D as being formed by a wedge-shaped clamp pad 164 and a shoe 166 of complementary shape. Alternatively, however, the clamping mechanism may be formed by a cam locking mechanism that automatically locks onto the rail under downward movement (with a controllable override to allow lowering of the rail).

[0113] Each composite support clamp unit 151 may be formed as a series of corresponding composite support clamp modules, the number of composite support clamp modules being at least sufficient to enable the clamping mechanism to support both the rotor-nacelle assembly and the carriage elevator 140 in use. Similarly, if separate support assemblies 150 and clamping mechanisms 160 are used, each clamping mechanism may be formed as a series of clamp modules, the number of clamp modules being at least sufficient to enable the clamping mechanism to support the rotor-nacelle assembly and the elevator carriage 140 in use.

[0114] Figs. 8A - 8C show the jacking of the elevator carriage 140 upwards of the wind turbine tower 110. The carriage chassis 142 of the elevator carriage 140 has a lower composite support clamp unit 151A and an upper composite support clamp unit 151B. The lower composite support clamp unit 151A forms a lower sub-assembly slidable along the rail 120A to which the elevator carriage 140 is attached, relative to an upper sub-assembly having the upper composite support clamp unit 151B and the chassis body 144, the relative movement being driven by a jacking ram 147.

[0115] In FIG. 8A, the lower composite support clamp unit 151A is closed and clamped onto the rail 120A. The jacking ram 147 is extended, thereby lifting the carriage body 144 (and the remainder of the elevator carriage 140) above the rail 120A to the position shown in FIG. 8B. Next, the upper composite support clamp unit 151B is closed and clamped onto the rail 120A. Next, the lower composite support clamp unit 151A is released to a slidably engaged but unclamped configuration. Next, as shown in FIG. 8C, the jacking ram 147 is retracted to raise the lower composite support clamp unit 151A. By repeating this procedure, the elevator carriage 140 and any load (e.g., the rotor-nacelle assembly 170) can be raised above the tower 110. By reversing this procedure, the elevator carriage 140 and any load can be lowered below the tower 110.

[0116] The elevator carriage 140 is provided with a nacelle pivot ram 149, whereby the rotor-nacelle assembly 170 can be pivoted when the carriage reaches the top of the tower 110, from a push-up orientation (e.g., as shown in FIGS. 8A - 8C, with the rotor axis of rotation oriented substantially downward, e.g., substantially vertically downward) in which the rotor-nacelle assembly is supported while the elevator carriage 140 is transporting the side of the tower upward, to an operating orientation (e.g., with the rotor axis of rotation oriented horizontally) that allows the nacelle to be connected to the top of the tower (e.g., by a yaw bearing that allows the nacelle to yaw with respect to the tower).

[0117] One or more rails may be provided on a single-section tower body. However, in the case of a large wind turbine assembly, the tower 110 may be formed from a plurality of tower sections 110’ as shown in FIG. 1. The tower sections 110’ are connected together during assembly, for example by connection bolts 115 as shown in FIG. 2A. Adjacent sections of the tower body may be connected together, and adjacent sections of the rails may also be connected together.

[0118] FIGS. 9A-9K illustrate steps in a method of assembling a wind turbine tower 110.

[0119] In FIG. 9A, an elevator carriage 140 is shown in a state where a carriage body 144 is releasably connected to a first rail 120A of an upright tower section 110A’, and a carriage arm 146 is releasably connected (e.g., supported) to a second rail 120B.

[0120] Figures 9B and 9C show a carriage adapter 180 (tower section support) connected to the elevator carriage 140, and Figure 9L shows a perspective view of the carriage adapter 180. (The connection between the carriage adapter 180 and the elevator carriage 140 is further shown in Figure 5F). The carriage adapter 180 is adapted to support the tower section 110B' while the tower section(s) 110A' erected by the elevator carriage 140 is / are being transported up and down. The carriage adapter 180 has a tower section support platform 182 for receiving the tower section 110B' to be transported. To fix (stabilize) the tower section 110B' on the carriage adapter 180, a clamp mechanism 184 (fixing mechanism) is provided on the carriage adapter (e.g., on the tower section support platform 182). The clamp mechanism 184 on the carriage adapter 180 fixes the tower section 110B' by traction force (resistance to shear resulting from static friction and any mechanical deformation of the clamped surface). The carriage adapter 180 may be size - changeable to enable the transportation of tower sections 110B' of different sizes (e.g., since one or more upper tower sections may have a smaller diameter than one or more lower sections, it is size - changeable to fix tower sections with different base diameters).

[0121] Next, the tower section 110B' to be transported is loaded onto the tower section support platform 182 of the carriage adapter 180 as shown in Figures 9D and 9E. The tower section 110B' can be placed on the tower section support platform 182 which can assist in aligning the height of the tower section 110B'. The clamp mechanism 184 is moved to a predetermined position (e.g., by a clamp alignment drive 184D) and is clamped onto the rail 120 of the tower section 110B' to fix the tower section on the carriage adapter 180.

[0122] Next, as shown in the side view of FIG. 9F and the plan view of FIG. 9I, the elevator car 140 is raised to the top of the upright tower section(s) 110A', and for example, the bottom of the tower section 110B' to be transported is slightly above the top of the upright tower section.

[0123] As shown in FIG. 9L, the tower section support platform 182 can have an upper platform section 182A for receiving the tower section 110B' to be transported, which is slidably engaged with a lower platform section 182B connected to the elevator car 140. The sliding movement of the upper platform section 182A relative to the lower platform section 182B is provided by a platform drive mechanism 182D (for example, a hydraulically operated piston).

[0124] Next, as shown in FIGS. 9G and 9J, the carriage adapter 180 slides the upper platform section 182A relative to the lower platform section 182B, for example, by sliding the transported tower section over the top of the upright tower section(s) 110A' so as to coaxially align the transported tower section 110B' with the upright tower section(s).

[0125] Next, the carriage adapter 180 connected to the elevator carriage 140 descends (e.g., by lowering the elevator carriage) until the transported tower section 110B' is placed on the upright tower section(s) 110A', as shown in the perspective view of FIG. 9H. Next, the transported tower section 110B' is connected to the top of the upright tower section(s) 110A' (e.g., by being bolted together using connection bolts 115), similar to what is shown in FIG. 2A. When the transported tower section 110B' is connected to the wind turbine tower 110, the carriage adapter 180 can release the clamp mechanism 184 from the transported tower section 110B' and then retract the upper platform section 182A from the wind turbine tower 110, as shown in FIG. 9K.

[0126] The tower 110 may be disassembled according to a procedure opposite to the tower assembly.

[0127] FIGS. 10A - 10C show consecutive steps in an alternative method of assembling the wind turbine tower 110 using an alternative carriage adapter 180'. Similar to FIGS. 9A - 9H, the carriage adapter 180' is adapted to support the tower section 110B' while the elevator carriage 140 transports the upright tower section(s) 110A' up and down. The carriage adapter 180' differs from the carriage adapter 180 of FIG. 9A in that it has a tower section pivoting mechanism 186 for pivoting the transported tower section 110B'.

[0128] Similar to the method described above, the transported tower section 110B' is loaded onto the carriage adapter 180', as shown in FIG. 10A. Then, the elevator carriage 140 is raised to the top of the upright tower section(s) 110A' such that, as shown in FIG. 10B, the bottom of the transported tower section 110B' is slightly above the top of the upright tower section.

[0129] Next, as shown in FIG. 10C, the tower section pivoting mechanism 186 of the carriage adapter 180 pivots the tower section 110B' to be transported about a vertical axis so that the tower section 110B' to be transported is aligned (e.g., coaxially) above the top of the upright tower section(s) 110A'. Next, the elevator carriage 140 is lowered until the tower section 110B' to be transported is placed on the upright tower section(s) 110A'. Next, the tower section 110B' to be transported is connected to the upright tower section(s) 110A', for example, by being bolted together. Pivoting the tower section 110B' to be transported to align it, as shown in FIGS. 10B and 11C, may be less mechanically complex than sliding the tower section to be transported, as shown in FIGS. 9F - 9H.

[0130] FIGS. 9B and 9C show a carriage adapter 180 connected to the elevator carriage 140, which has a clamping mechanism 184 for fixing to the tower section 110B' to be transported by a traction force (resistance to static friction and shear forces resulting from any mechanical deformation of the clamped surface). FIGS. 11A - 11D show an alternative system for fixing the tower section 110B'' to the carriage adapter 180', which differs in that the fixing mechanism 184' is provided with an extendable fixing pin 185 for fixing to the tower section 110B' by mechanical engagement with a complementary pin receiving structure (hole) 110H within the tower section 110B''. The pin receiving structure 110H is provided in proximity to the base 117 of the tower section 110B''. The pin receiving structure 110H may be provided on the rail 120, which can allow for better distribution of the forces across the body 116' of the tower section 110B'' that occur during use. The carriage adapter 180' may be size - changeable to enable it to transport tower sections 110B'' of different sizes.

[0131] Figures 11C and 11D respectively show, in plan view, the tower section 110B'' received on the tower section support platform 182 of the carriage adapter 180' before and after the fixing pin 185 is extended into the pin receiving structure 110H to fix the tower section 110B'' for transportation by the elevator carriage 140. The fixing pin 185 can be moved between an extended position and a retracted position by respective actuating mechanisms.

[0132] As shown in FIGS. 9F and 9G, when the tower section 110B'' is lifted to a fixed position by the elevator carriage 140, the tower section 110B'' slides to the top of the upright tower section(s) 110A. As shown in FIG. 11A, the tower section support platform 182 can have an upper platform section 182A that slidably engages a lower platform section 182B of the platform connected to the elevator carriage 140. The sliding movement of the upper platform section 182A relative to the lower platform section 182B is provided by a platform drive mechanism 182D (e.g., a hydraulically operated piston).

[0133] As shown in FIG. 9D, the wind turbine tower 110 may be provided with a fixed level access platform 112F. Additionally, the wind turbine tower 110 may be provided with a variable level access platform 112V as shown in FIGS. 12A - 12D.

[0134] As shown in FIGS. 12B and 12C, a variable level access platform 112V can be aligned with a fixed level access platform 112F to provide a composite access platform assembly 112C that provides an access platform around the wind turbine tower 110. By extending completely around the wind turbine tower 110, the composite access platform assembly 112C forms a safety platform that allows an operator to rappel outside the wind turbine tower at any position around the wind turbine tower (e.g., in the case of an emergency evacuation, allows rappelling from the nacelle at the top of the wind turbine tower regardless of the yaw direction of the nacelle).

[0135] As shown in FIGS. 9D, 10A, and 12A, during the construction (or disassembly) of the wind turbine 100, providing an access platform that extends completely around the wind turbine tower 110 as a composite access platform assembly 112C with a variable level access platform 112V allows the movement of an elevator carriage 140 up and down the wind turbine tower 110. The variable level access platform 112V may be left at or near the bottom of the wind turbine tower 110 during construction (e.g., clamped to the rails 120), or the variable level access platform 112V may remain connected to the elevator carriage 140 (e.g., to facilitate operator access to the elevator carriage).

[0136] As shown in FIG. 9C, before completing the assembly of the wind turbine tower 110, a variable level access platform can be attached to the bottom section 110A' of the wind turbine tower 110. For example, both the fixed level access platform 112F and the variable level access platform 112V may be attached onto the floating foundation on land or near the quay before the floating foundation 114 proceeds to the installation site.

[0137] Once the wind turbine tower 110 is assembled, the variable level access platform 112V can be connected below the elevator carriage 140 and raised to the same level as the fixed level access platform 112F (e.g., providing a flat walkway for workers) in a dedicated method step or when raising the rotor-nacelle assembly 170 for attachment to the wind turbine tower, as shown in FIG. 12B. Next, the variable level access platform 112V can be fixedly attached in place by bolting or otherwise connecting it to the wind turbine tower 110 (e.g., by clamping it to rails) or by bolting or otherwise connecting it to the fixed level access platform 112F (or by a combination of such attachment methods). Raising the variable level access platform 112V using the elevator carriage 140 enables the variable level access platform to be of low complexity without the need for a separate drive mechanism.

[0138] After the variable level access platform 112V is attached at the same level as the fixed level access platform 112F, the elevator carriage 140 may be disconnected from the variable level access platform 112V. The elevator carriage 140 can then continue to raise the wind turbine tower 110 with a load (e.g., the rotor-nacelle assembly 170 or a tower section 110'), or if the elevator carriage is not carrying a load, the elevator carriage can be removed from the wind turbine tower (e.g., by a crane or by an alternative mechanism for transferring the elevator carriage to a ship). Similarly, the elevator carriage 140 can be used to lower the variable level access platform 112V below the level of the fixed level access platform 112F.

[0139] The variable-level access platform 112V can also be further raised above the wind turbine tower 110 by the elevator carriage 140 to facilitate high-level access by an operator, as shown in FIG. 12D. For example, the raised variable-level access platform 112V can enable inspection or maintenance access to the wind turbine blade 170B when the blade is rotated to a position where it extends downward.

[0140] Instead of (or in addition to) the variable-level access platform 112V being raised and lowered by the elevator carriage 140, the variable-level access platform may be provided with a platform drive mechanism that engages with one or more rails 120 of the wind turbine tower 110 and enables the variable-level access platform to be independently raised and lowered. Providing a platform drive mechanism allows the elevator carriage 140 to be removed from the wind turbine tower 110 before the variable-level access platform is moved to the same level as the fixed-level access platform 112F, allows the elevator carriage to be removed from a lower position on the side of the wind turbine tower, and allows the elevator carriage to be more easily removed (e.g., enabling removal using a smaller crane or by transferring to a ship without using a crane). The independent movement of the variable-level access platform 112V also allows the variable-level access platform to be moved to different heights without the need for the elevator carriage to be present on the wind turbine tower.

[0141] Alternatively, the variable-level access platform 112V may be raised and lowered by a winch mechanism, such as a winch mechanism that engages with or is attached to the fixed-level access platform 112F.

[0142] The construction and assembly of the wind turbine assembly are shown using a floating foundation in the ocean, but the construction and assembly can also be used, for example, for onshore wind turbine assemblies having a firm foundation on the ground.

[0143] The figures provided in this specification are schematic and not to scale.

[0144] Throughout the description and claims of this specification, the terms "comprise" and "contain" and their variants mean "including but not limited to", and are not intended to (and do not) exclude other parts, additives, components, integers or steps. Throughout the description and claims of this specification, unless the context requires otherwise, the singular form includes the plural. In particular, when an indefinite article is used, this specification should be understood as contemplating both plural and singular, unless the context requires otherwise.

[0145] Features, integers, and characteristics described in connection with a particular aspect, embodiment, or example of the invention are to be understood as applicable to any other aspect, embodiment, or example described herein, unless they are incompatible therewith. All of the features disclosed in this specification (including any appended claims, abstract, and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not limited to the details of any of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any appended claims, abstract, and drawings), or any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0146] Attention is directed to all papers and documents which are filed herewith or prior hereto in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are hereby incorporated by reference into this specification.

Claims

1. A wind turbine tower elevator carriage for clamping onto at least a first tower rail, wherein the first tower rail extends upwardly of a wind turbine tower for releasably supporting the carriage thereon, and the elevator carriage comprises: a carriage body; a first releasable rail clamp and a second releasable rail clamp operable independently; a lifting mechanism for raising and lowering the carriage body relative to the first releasable rail clamp; A wind turbine tower elevator carriage comprising the above.

2. The elevator carriage according to claim 1, further comprising a nacel support for supporting a wind turbine nacel in a nacel push-up position while the elevator carriage ascends the wind turbine tower.

3. The elevator carriage according to claim 2, wherein the elevator carriage comprises a carriage chassis, and the nacel support is pivotable relative to the carriage chassis about a substantially vertical axis when the elevator carriage is attached to a side of the wind turbine tower.

4. The elevator carriage according to claim 2 or 3, wherein the nacel support is provided with a nacel transfer mechanism for transferring the wind turbine nacel from the nacel push-up position to the top of the wind turbine tower.

5. The elevator carriage according to any one of claims 1 to 4, further comprising a tower section support for supporting a wind turbine tower section in a tower section push-up position while the elevator carriage ascends the wind turbine tower.

6. The elevator carriage according to claim 5, wherein the tower section support is provided with a tower section transfer mechanism for transferring the wind turbine tower section from the tower section push-up position to the top of the wind turbine tower.

7. Each releasable rail clamp comprises: a rail clamp body; opposing rail clamp pads for clamping onto the rail; a pad actuator; and comprises the above. The rail clamp pad is a wedge-shaped pad and has a first pad surface for contacting the rail and a second opposing pad surface received in a complementary-shaped shoe, and the second pad surface is not parallel to the first pad surface. The elevator carriage according to any one of claims 1 to 6, wherein the pad actuator is operable to move the wedge-shaped pad substantially parallel to the shoe and to the length of the rail.

8. The rail clamp comprises a clamp chassis having opposing clamp arms for supporting respective rail clamp pads, a clamp pivot actuator, and is provided with, The elevator carriage according to any one of claims 1 to 7, wherein the clamp pivot actuator is operable to pivot the clamp arm relative to the opposing clamp arm between an open configuration and a closed configuration.

9. The elevator carriage according to claim 8, wherein the clamp arm is provided with a releasable self-locking linkage for holding the clamp arm in the clamped position.

10. The elevator carriage according to claim 8 or 9, wherein the clamp pivot actuator is operable to pivot the clamp arm relative to the clamp chassis between the open configuration and the closed configuration.

11. The elevator carriage according to any one of claims 1 to 10, wherein the clamp chassis has a base for supporting against the bearing surface of the rail.

12. Each releasable rail clamp comprises a repeated assembly of a rail clamp module, the elevator carriage according to any one of claims 1 to 11.

13. The elevator carriage comprises a carriage arm connected to the carriage body, and the reaction arm comprises a lateral support assembly and a support arm actuator for engaging the lateral support assembly with the wind turbine tower, the elevator carriage according to any one of claims 1 to 12.

14. The elevator carriage according to claim 13, wherein the lateral support assembly comprises a first support member for engaging the outer surface of the tower body of the wind turbine tower.

15. The elevator carriage according to claim 13 or 14, wherein the lateral support assembly comprises a second support member for engaging with a second tower rail of the wind turbine tower.

16. The elevator carriage according to claim 15, wherein the second support member is configured to engage with a side surface of the second tower rail proximate to the first tower rail.

17. The elevator carriage according to claim 16, wherein the second support member is configured to releasably receive the second tower rail therein.

18. The elevator carriage according to any one of claims 13 to 17, wherein the carriage arm comprises one or more extendable arm members for varying a separation between the carriage body and the lateral support assembly.

19. The elevator carriage according to any one of claims 13 to 18, wherein the elevator carriage comprises opposing carriage arms.

20. A method of assembling a wind turbine tower having a tower body and a rail extending upwardly from the tower body, wherein the tower comprises a plurality of tower sections connected in series, each tower section having a respective tower body section and a respective section of the rail, the method comprising: erecting a first tower section; providing an elevator carriage on the rail of the first tower section; loading a second tower section onto the elevator carriage when the elevator carriage is in a first position; transporting the second tower section by raising the elevator carriage above the rail to a second position, the second position being higher than the first position; transferring the second tower section onto the first tower section using the elevator carriage; connecting the second tower section to the first tower section. A method comprising the above steps.

21. Loading the second tower section onto the elevator car is operable by a clamping mechanism or a fixing mechanism operable by inserting a fixing pin into complementary receiving structures within the tower section to releasably fix the second tower section to a tower section support platform, the method according to claim 20.

22. Transferring the second tower section onto the first tower section includes sliding the second tower section to align it with the first tower section, the method according to claim 20 or 21.

23. Transferring the second tower section onto the first tower section includes pivoting the second tower section to align it with the first tower section about a vertical axis, the method according to claim 20 or 21.

24. The method loading a wind turbine nacelle onto the elevator car in a third position, raising the elevator car to a fourth position, transferring the nacelle to the top of the wind turbine tower using the elevator car, connecting the nacelle to the top of the wind turbine tower, further comprising the method according to any one of claims 20 to 23.

25. A wind turbine tower having a tower body and rails extending upward from the tower body, the rails having an outer surface (S1) oriented away from the tower body and opposing side surfaces (S2, S3, S4) connecting the outer surface (S1) to the tower body, each of the opposing side surfaces having a channel extending along the rail, the channel including a clamping surface (S2) adjacent to a first support surface (S3), the clamping surfaces of the opposing side surfaces being parallel to a central plane (CP) extending outward from the tower body through the center of the width (B) of the base of the rail in the tower body, for each pair of opposing side surfaces, the first support surface is inclined toward the clamping surface and is angled by a first angle of 30° to 60° with respect to the central plane (CP), a wind turbine tower.

26. Each of the opposing side faces further comprises a second bearing surface, and the clamping surface is between the first bearing surface and the second bearing surface. For each pair of opposing side faces, the second bearing surface is inclined towards the clamping surface and is angled by a second angle of 30° to 60° with respect to the central plane (CP). The wind turbine tower according to claim 25. **Claim 27** The tower comprises three or more rails extending upwardly of the tower, and the rails are spaced apart around the tower in a rotationally symmetric arrangement. The wind turbine tower according to claim 25 or 26. **Claim 28** A wind turbine tower having a tower body and three or more rails extending upwardly of the tower body, wherein the centers of adjacent rails are spaced apart by at least 80° or a linear separation of at least 2 m around the center of the tower body. A wind turbine tower. **Claim 29** The centers of adjacent rails are spaced apart by at least 90° around the center of the tower body. The wind turbine tower according to claim 28. **Claim 30** The wind turbine tower has three rails, and the centers of adjacent rails are spaced apart by 100° to 160° around the center of the tower body. The wind turbine tower according to claim 28 or 29. **Claim 31** The centers of the rails are spaced apart around the center of the tower body in a rotationally symmetric arrangement. The wind turbine tower according to any one of claims 28 to 30. **Claim 32** The tower comprises a tower body having an outer surface with a circular cross-sectional shape, and the rails project from the outer surface of the tower body. The wind turbine tower according to any one of claims 28 to 31. **Claim 33** Each rail has an outer surface (S1) oriented away from the tower body and opposing side faces (S2, S3, S4) connecting the outer surface to the tower body, each of the opposing side faces having a channel (CH) extending along the rail, the channel including a clamping surface (S2) adjacent to a first bearing surface (S3), the clamping surface (S2) of the opposing side face being parallel to a central plane (CP) extending outwardly from the tower body through the center of the width (B) of the base of the rail in the tower body. For each opposing side, the first bearing surface (S3) is inclined towards the clamping surface (S2) and is angled by a first angle of 30° to 60° with respect to the central plane (CP). The wind turbine tower according to any one of claims 28 to 32.

34. Each of the opposing sides of the rail further comprises a second bearing surface (S4), and the clamping surface (S2) is between the first bearing surface (3) and the second bearing surface (S4). For each opposing side, the second bearing surface (S4) is inclined towards the clamping surface (S2) and is angled by a second angle of 30° to 60° with respect to the central plane (CP). The wind turbine tower according to claim 33.

35. The rail or each rail is hollow. The wind turbine tower according to any one of claims 25 to 34.

36. The rail or each rail is braced between the clamping surfaces and comprises internal reinforcement members extending upwardly of the tower. The wind turbine tower according to claim 35.

37. The rail is welded to the tower body along the length of the rail. The wind turbine tower according to any one of claims 25 to 36.

38. The tower has a cylindrical tower body. The wind turbine tower according to any one of claims 25 to 37.

39. The tower body comprises a plurality of tower body sections connected in series, and each rail comprises a corresponding plurality of rail sections provided in each tower body section. The wind turbine tower according to any one of claims 25 to 38.

40. A wind turbine tower assembly, a wind turbine tower, a fixed level access platform, a variable level access platform configured to form an access platform assembly that extends completely around the wind turbine tower, comprising a wind turbine tower assembly.

41. The wind turbine tower has a tower body and a rail extending upwardly of the tower body. The wind turbine tower has an elevator carriage, and the elevator carriage is configured to engage the rail to raise and lower the elevator carriage upwardly of the wind turbine tower. The variable-level access platform of the wind turbine tower assembly according to claim 40, which is configured to form a releasable connection with the elevator carriage to raise and lower the variable-level access platform.

42. The wind turbine tower has a tower body and rails extending upward from the tower body. The variable-level access platform of the wind turbine tower assembly according to claim 40, which comprises a platform drive mechanism for engaging with the rails to raise and lower the variable-level access platform.

43. The variable-level access platform of the wind turbine tower assembly according to any one of claims 40 to 42, which includes releasably connecting the variable-level access platform to the fixed-level access platform and is configured to be attached to the wind turbine tower.

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