Connector assembly

Abstract

The invention describes a connector assembly (1) for connecting two components (2A, 2B), comprising a stud (10) comprising a shank (10S) and a threaded portion (10T) at each end of the shank (10S); a first threaded insert (14A, 14B) for embedding in the component (2A), adapted to engage with a first threaded portion (10T) of the stud bolt (10); a second threaded insert (14A, 14B) for insertion in another component (2B), adapted to engage with a second threaded portion (10T) of the stud bolt (10); and a spacer (16) dimensioned to enclose the shank (10S) of the stud bolt (10) and comprising length adjustment means (16T) for adjusting the length of the spacer (16) between the initial length (L0) and the maximum extension length (L1). The invention further describes a wind turbine rotor blade comprising a first rotor blade segment (2A) and a second rotor blade segment (2B), and a plurality of such connector assemblies (1) arranged to connect the first rotor blade segment (2A) to the second rotor blade segment (2B); and a method of connecting a first wind turbine rotor blade segment (2A) to a second wind turbine rotor blade segment (2B) using a plurality of such connector assemblies (1).

Description

TECHNICAL FIELD

[0001] Rotor blades of wind turbines can have a length of 80 m or more. Due to infrastructure limitations, it can not always be possible to transport such long rotor blades by road or rail. Therefore, in order to install a wind turbine having such long rotor blades, each rotor blade can be provided as two or more segments that can be assembled on site. BACKGROUND

[0002] There are various ways of manufacturing rotor blade segments such that these rotor blade segments can be connected to form a robust joint. In one method, the joint is formed by an arrangement of parallel bolts that are screwed into threaded inserts that were previously embedded in the outer ends of the rotor blade segments. In order to provide the strength required for such a connection, the bolts are usually pre-tensioned. In a "long" rotor blade as described above, the width of the airfoil at the joint between the rotor blade segments can be about 2-3 m. In order to ensure the structural strength of such a wide joint, it is desirable to use a dense arrangement of bolts on each side of the chord plane, with the bolts being arranged mainly in the thicker parts of the airfoil.

[0003] In one method, the connector assembly can comprise a pair of collinear double-ended stud bolts. Each stud bolt extends through an opening in the end of the intermediate part, with one end of the bolt being screwed into an embedded insert in the rotor blade segment and the other end being secured with a nut. The load carrying properties required of the connector assembly usually determine the minimum diameter of each stud bolt and its minimum length. A problem with such a connector assembly is the bulk of the intermediate part, which often has to be dimensioned to accommodate the head of a wrench so that the nut can be tightened. Therefore, the number of bolted connections in the joint between the rotor blade segments is limited by the width of the intermediate part of the connector assembly, and the distance between the stud bolts of an adjacent prior art connector assembly can be disadvantageously large.

[0004] It is therefore an object of the present invention to provide an improved connector assembly that overcomes the problems outlined above.

[0005] This object is achieved by the claimed connector assembly, the claimed method of connecting wind turbine rotor blade segments, and the claimed wind turbine rotor blade. SUMMARY

[0006] According to the invention, a connector assembly is for connecting two components of an object and comprises a single stud having a shank and a threaded portion at each end of the shank; a first threaded insert for embedding in one of the components, adapted to engage with the first threaded portion of the stud; and a second threaded insert for embedding in the other component, adapted to engage with the second threaded portion of the stud. The connector assembly of the invention further comprises a spacer sized to accommodate the shank of the stud, and length adjustment means for adjusting the length of the spacer between an initial length and a maximum extended length to apply a pretension to the stud. The threaded inserts, the spacer and the stud are separate components.

[0007] It will be appreciated that when the target components are connected by this type of double-ended stud, a gap must necessarily be maintained between the target components. In the following, this gap can be referred to as a "pre-gap". The spacer in place on the stud shank is understood to extend across this pre-gap between the target components. The spacer is understood to have a substantially hollow and tubular form to accommodate the stud shank, i.e. the spacer is open at both ends. When the spacer extends to its maximum extended length, its end faces will press against the opposing end faces of the rotor blade segments in an attempt to widen the gap, which is not possible (the rotor blade segments cannot be pushed apart due to the stud and threaded inserts). Thus, a pretension force is established in each stud, achieving a secure connection between the rotor blade segments. In the following, the terms "spacer", "pretension component" and "bolt pretensioner" have the same meaning and can be used interchangeably.

[0008] An advantage of the connector assembly of the invention is that its widest dimension can advantageously be compact, i.e. the connector assembly can advantageously be narrow. This allows a greater density of studs to be deployed in the joint between the two components.

[0009] According to the invention, a wind turbine rotor blade comprises a first rotor blade segment and a second rotor blade segment, and a plurality of connector assemblies of the invention arranged to connect the first rotor blade segment to the second rotor blade segment. The load carrying properties of the wind turbine rotor blade of the invention can be improved over an equivalent prior art segmented rotor blade by the higher possible density of studs forming the stud joint between the segments. Furthermore, the combined weight of the connector assemblies is less than the combined weight of an equivalent prior art connector assembly of the same number due to the relatively slender spacers of the connector assemblies.

[0010] According to the present application, the method of connecting first wind turbine rotor blade segments to second wind turbine rotor blade segments with a plurality of such connector assemblies comprises the initial step of embedding the first and second threaded inserts of each connector assembly co-linearly in the end faces of the rotor blade segments (i.e. each second insert is in line with the first insert such that the longitudinal axes of each pair of inserts are substantially co-linear). Subsequently, the first end of each stud is threaded into the first threaded insert and then an adjustable length spacer is placed over the shank of each stud. In the next step, the second end of each stud is threaded into the corresponding second threaded insert. At the completion of these steps, the rotor blade segments are joined by the studs. In the final step, each spacer length is extended to fill the gap between the end faces of the rotor blade segments and to apply a pre-tension to the corresponding studs as required. Assembly of the rotor blade can then be completed by placing a fairing around the pre-gap between the rotor blade segments to form a substantially closed surface.

[0011] Particularly advantageous embodiments and features of the present application are given by the dependent claims, as disclosed in the following description. Features of different claim categories can be combined as appropriate to give further embodiments not described herein.

[0012] The threaded inserts can be cylindrical tubes shaped to fit into the holes formed in the transition pieces and long enough to accommodate one end of the stud. Alternatively, the threaded inserts can be in the form of T-bolts. Without limiting the application in any way, the following mainly relates to the cylindrical tube implementation.

[0013] The connector assembly of the present application can be used to connect any components that benefit from this type of stud connection. In the following, without limiting the application in any way, it can be assumed that the objects being assembled are wind turbine rotor blades and each component is a rotor blade segment.

[0014] The expressions "threaded insert" and "insert" are to be understood as synonyms and can be used interchangeably in this text. The joint end of each rotor blade segment can be prepared in a well-established manner by embedding the tapered transition piece as an extension of the spar cap in the composite material layers during the manufacturing lay-up and curing phase. To receive the threaded inserts, appropriately deep holes can be formed in the end faces of the transition pieces.

[0015] In the following, it can be assumed that the wind turbine rotor blades are segmented to overcome the transportation difficulties as explained above. This is typically the case for wind turbine rotor blade lengths of 80m or more. In the case of rotor blades of this size, the spanwise length of the joint between rotor blade segments, i.e. the overall length of the connector assembly (measured between the outer ends of the two inserts) can be about 1m.

[0016] In a preferred embodiment of the application, the joint between two rotor blade segments comprises 5-8 examples of the connector assembly of the application between a pair of transition pieces arranged on each side of the rotor blade.

[0017] Compared to prior art connector assemblies, the connector assemblies of the application can be arranged closer together. This means that, for a rotor blade joint comprising the same number of connector assemblies, the transition pieces can be made significantly narrower, requiring less material.

[0018] Alternatively, with the closer spacing between the connector assemblies of the application, the transition pieces can be kept "wide" and a greater number of connector assemblies can be used instead. This approach can be preferred because it does not require redesign of the transition piece, and because it increases the strength of the joint, allowing the joint between rotor blade segments to be moved further inwards (towards the root). For reasons of structural loading, segmented rotor blades with longer tip segments and shorter root segments can be preferred.

[0019] The stud can be a full-bodied stud, i.e. its shank diameter is the same as the major diameter of the thread. The stud can have a length of approximately 350 mm, and the thread at each end can extend over a length of 100 mm or more. The threaded portion of the insert can be located at a distance from the end of the insert. Adjacent to the threaded portion, the insert can be shaped as a plain cylinder having a diameter at least as large as the major diameter of the bolt thread (to accommodate the bolt in the first assembly step). In an exemplary embodiment, the stud has a diameter of 36 mm, e.g. a standard M36 bolt. The threaded ends of the stud have the same handedness.

[0020] As explained above, the transition piece is prepared by forming holes in the stack-up of the transition piece to accommodate the required number of threaded inserts. Preferably, each hole is formed to a depth sufficient to accommodate a threaded insert, and each threaded insert is long enough to fully contain the end of its stud. During the assembly phase, the stud is threaded into the first threaded insert, and after the spacer is placed, the stud is then turned in the opposite direction so as to thread its other end into the second threaded insert, moving its first threaded end "backwards" in the first insert some distance. At the completion of this phase, both threaded ends of the stud are engaged with threaded inserts.

[0021] To facilitate rotation of the stud of the connector assembly, its shank can have surface features shaped to engage with a device for rotating the stud. In a preferred embodiment of the invention, the shank of the stud comprises surface features over some of its length, which are arranged to engage with corresponding features on the inside of the spacer. These can be any suitable polygonal shape, for example complementary triangular, square or hexagonal shapes. Since the spacer is in place on the shank of the stud when the stud is rotated to engage with the second threaded insert, it is preferred that the spacer comprises external surface features to engage with a rotating tool, for example the spacer can comprise a hexagonal portion to engage with a tool such as an end opening spanner or spanner.

[0022] The length of the spacer of the connector assembly of the invention can be extended from an initial minimum length to a maximum length. To this end, the spacer has length adjustment means. This can be achieved in any suitable way. For example, in a particularly preferred embodiment of the invention, the spacer can be a two-part piece, with means to move one part relative to the other in an axial direction. In one embodiment, the length adjustment means can be implemented as a ratchet arrangement, with a toothed linear rack formed on one spacer part, and a spring-loaded pawl on the other spacer part, to engage with the teeth of the rack when the first and second spacer parts are pushed apart to extend the length of the spacer.

[0023] In a more economical and therefore preferred embodiment of the invention, the spacer is assembled from two or more simple tubular sections. Two adjacent tubular sections are preferably joined by a threaded interface, so that one section can be screwed onto the other. In the following, it shall be assumed that one end of the first tubular section has an external thread, and one end of the second tubular section has a corresponding internal thread. With the second tubular section fully screwed onto the first tubular section, the spacer has its initial (minimum) length. To extend the spacer, the second tubular section is partially "unscrewed" from the first tubular section. In this embodiment, the threaded interface is also the length adjustment means. Preferably, the lead of the threaded interface is chosen to facilitate the desired length extension. In an exemplary embodiment, the lead is chosen so that the spacer or "pretensioned bushing" extends a distance equivalent to the pitch of the stud (e.g. 4 mm in the case of an M36 stud) per turn. For each full turn of one tubular section relative to the other, the tubular sections move apart this amount.

[0024] Instead of a threaded interface with multiple helical grooves with inclined flanks, the two spacer parts can meet at a single helical feature, allowing for a relatively small length extension. Rotating one spacer part by no more than one full turn ensures that the complementary faces of the two spacer parts remain in partial contact.

[0025] The airfoil components of wind turbine rotor blades can be subjected to large loads during operation, and thus the joints between segments of segmented rotor blades must bear these loads. Each connector extending between rotor blade segments contributes to the strength of the connection, and a dense arrangement of connectors is generally preferred, i.e., an advantageously low stud bolt pitch (the distance between the midpoints of adjacent stud bolts). As explained above, prior art connector assemblies are relatively bulky, and the number of connectors is limited by the width of each connector assembly. Therefore, the stud bolt pitch in prior art connector assemblies can be disadvantageously large, for example, about 75 mm. This problem is overcome by the connector assembly of the present invention, which allows for advantageously low stud bolt pitches. For example, the diameter of the stud bolt (defining the minimum inner diameter of the spacer) can be 36 mm, and the outer diameter of the spacer can be at most 55 mm. With a gap of 10 mm between the spacers to allow for the placement of rotating tools, the stud bolt pitch is only 65 mm.

[0026] To facilitate the length extension process, the spacer of the connector assembly of the present invention preferably includes a plurality of surface features for engaging with a tool to adjust the length of the spacer. In a particularly preferred embodiment of the invention, the surface features are hexagonal cross-sectional shapes along at least a portion of the spacer, shaped to engage with a tool such as an end-opening screwdriver or wrench. This surface feature of the spacer can be arranged at any suitable location along the spacer, for example toward the center of a tubular section of the spacer. Alternatively or additionally, such a surface feature can be implemented in the form of a sprocket having gear teeth extending radially outward from the spacer. After the connector assembly is fabricated, a matching chain can be arranged around the sprocket and also around another motor-driven chain wheel. In a manner similar to a bicycle drivetrain, the chain wheel causes the chain to rotate, thereby rotating the spacer component.

[0027] The two components of the spacer can be provided with appropriate surface features. For example, one spacer component can be formed with relatively flat outer surface areas, thereby allowing the spacer component to be kept stationary by a suitable tool; the other spacer component can be formed with the surface features described above, thereby allowing the spacer component to be rotated using an open-end hexagonal wrench, chain, etc.

[0028] Any such surface feature is preferably arranged such that the surface feature of one spacer does not interfere with the surface features of its adjacent spacers during the fastening process, as will be explained below.

[0029] As indicated above, it is generally desirable to deploy the stud bolts in a dense arrangement, i.e., adjacent stud bolts are preferably close together; however, such placement is constrained by the width of the connector assembly and any required clearance for assembly and fastening. However, compared to prior art connector assembly designs based on two separate collinear studs, the structural strength of the joint made with the arrangement of the connector assembly of the present invention is advantageously high due to the single-piece stud bolts. Furthermore, the spacers of the connector assembly of the present invention are essentially closed cylinders, and are therefore structurally very efficient (with respect to their area moment of inertia), and thus require less material than conventional open or "bathtub" spacers. The design of the present invention facilitates narrower spacers, advantageously close placement of adjacent connector assemblies, and a correspondingly dense arrangement of stud bolts.

[0030] In another preferred embodiment of the invention, dense placement of connector assemblies is facilitated by incorporating structural asymmetry in the design of the spacers and arranging the connector assemblies in an alternating or head-to-toe arrangement. For example, in a preferred embodiment of the invention, the surface features for engaging with a rotating tool are offset from the center of the spacer. These surface features are in an alternating or head-to-toe arrangement when all spacers are in place between rotor blade segments. Similarly, the tubular segments of the threaded engagement spacers can have unequal lengths, i.e., the threaded engagement between segments of a two-part spacer can be offset from the center of the spacer. Longer spacer segments can be formed to include surface features for engaging with a rotating tool. Attached Figure Description

[0031] Other objects and features of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings. However, it should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0032] Figure 1 The joint between the rotor blade segments of a wind turbine is shown; Figure 2 Parts illustrating an exemplary embodiment of the connector assembly of the present invention; Figure 3 and Figure 4 The diagram illustrates the stages of the method of the present invention; Figures 5 to 7 An alternative embodiment of the connector assembly of the present invention is shown; Figure 8 This illustrates a prior art connection between segments of a wind turbine rotor blade.

[0033] In the figures, similar reference numerals always refer to similar objects. The objects in the figures are not necessarily drawn to scale. Detailed Implementation

[0034] Figure 1 An exemplary joint between two segments 2A, 2B of a wind turbine rotor blade is shown. The joint end of each segment 2A, 2B is prepared by forming a tapered transition member 22 as an extension of the sparsity cap 20 and embedding it into the composite material layer during the layup and curing stages of manufacturing. In each flared member 22, a series of parallel holes or blind holes are formed to the desired depth, and a threaded insert is placed in the appropriate position in each hole 24.

[0035] Rotor blade segments 2A and 2B will be connected by multiple examples of connector assemblies 1 of the present invention, for example, having 5-8 connector assemblies 1 on the suction side of the joint and a similar number of connector assemblies 1 on the pressure side of the joint.

[0036] Figure 2 and Figure 3 Parts of an exemplary embodiment of the connector assembly 1 of the present invention are shown. The elements of the connector assembly 1 of the present invention are: a double-ended stud bolt 10; a first threaded insert 14A having internal threads to match the threads at one end of the stud bolt 10; a second threaded insert 14B having internal threads to match the threads at the other end of the stud bolt 10; and a length-adjustable spacer 16 that engages with the stud bolt 10. For clarity, Figure 2 A two-part spacer 16 separate from the bolt 10 is shown, and the opposite ends of the rotor blade sections 2A, 2B in which threaded inserts 14A, 14B are embedded are indicated.

[0037] In this exemplary embodiment, the stud bolt 10 has an external feature 10H shaped to engage with a complementary internal feature 162H of the spacer 16, indicated by a dashed line in the corresponding spacer segment 162. Here, the spacer 16 includes two cylindrical or tubular segments 161, 162, each segment 161, 162 being provided with a straight thread to form a threaded engagement 16T when one segment 161, 162 is screwed onto the other segment 161, 162. The thread lead can be configured to produce a desired length extension per turn, for example, a length extension corresponding to the pitch of the stud bolt threaded portion. Surface features 161F, 162F on the spacer 16 are configured to engage with corresponding tools, as will be explained below. Figure 3 The surface features 161F and 162F of the spacer 16 are shown to be offset by different lengths 161D and 162D from the respective spacer ends, thereby allowing for a favorable dense arrangement of the connector assembly.

[0038] By rotating one component 161 of the spacer 16 relative to another component 162, the length of the spacer 16 can be adjusted from, for example, the length of the spacer 16 can be adjusted from, as shown in the figure. Figure 3The initial minimum length L0 shown is adjusted to the final length L1 (the expected gap length between segments 2A and 2B), wherein the annular outer end of the spacer 16 presses against the end faces of rotor blade segments 2A and 2B, as shown. Figure 3 As shown (the relevant components of rotor blade segments 2A and 2B are indicated by dashed lines). With the spacer 16 extending to press against the end faces of rotor blade segments 2A and 2B, the force generated against each end face is transmitted to the threaded interface between the stud bolt 10 and its inserts 14A and 14B, effectively pre-tensioning the stud bolt 10, as indicated by the opposite axial arrow at the threaded end 10T of the stud bolt 10. The force required to achieve the extended spacer length L1 determines the magnitude of the pre-tension on the stud bolt 10, and preferably, the spacer 16 extends entirely with substantially the same force, such that all stud bolts 10 are pre-tensioned to the same degree.

[0039] In the initial stage, one end of the stud bolt 10 of the connector assembly is screwed into the first insert 14A. This can be done by engaging the surface feature 10H on the shank 10S of the stud bolt 10 with a suitable tool, or by rotating the spacer 16 with the stud bolt 10 together with a suitable tool after placing the spacer 16 of the connector assembly on the stud bolt 10 such that its internal hexagonal feature 162H engages around the surface feature 10H of the stud bolt 10.

[0040] Then, screw the other end of the stud bolt 10 into the second insert 14B, and use a suitable tool to rotate the spacer 16 together with the stud bolt 10. Rotating the spacer 16 causes the bolt 10 to rotate as well, so that the second end of the stud bolt 10 engages with the threaded portion of the second insert 14B. As a result of this rotation, the first end of the stud bolt 10 retracts a certain distance within the first insert 14A. The stud bolt 10 is now in place and connects the two components 2A, 2B. The tools W1, W2 can be any suitable wrench as indicated here, or any other type of tool that can engage with the relevant features of the stud bolt and the spacer.

[0041] In the subsequent stage, the joint between rotor blade sections 2A and 2B is pre-tensioned. For example... Figure 3As illustrated, one component 162 of each spacer 16 is held stationary using a suitable tool, while the other component 161 is rotated using another suitable tool. For example, a screwdriver W2 can engage with a relatively flat area 162F on the second spacer segment 162 to hold it in place, while an open-end wrench W1 can engage with a hexagonal surface feature 161F on the first spacer component 161 to rotate it relative to the second spacer segment 162. In this way, spacer segments 161, 162 are forced apart, extending the spacer 16 to its final length L1 and loading the opposing faces of transitions 2A, 2B, thereby pre-tensioning the bolt 10 as indicated by the arrows.

[0042] like Figure 3 As shown in the plan view, the spacers 16 are preferably arranged in a staggered manner. This allows the spacers 16 to be advantageously arranged "densely" without interference between the tools W1, W2 used to fasten a spacer and the surface features 161F, 162F of adjacent spacers.

[0043] Repeat these steps until all the post bolts 10 of all connector assemblies are in place, holding the two rotor blade segments 2A and 2B together, as shown. Figure 4 As shown in the perspective view, the spacers 16 of connector assembly 1 are separated by an advantageously small gap D1. This allows for the use of a greater number of spacers (compared to prior art connectors that incorporate the same transition pieces). Similarly, the closer spacing allows for the use of narrower transition pieces 22.

[0044] Once all the column bolts 10 have been pre-tensioned as described above, the joint area between rotor blade segments 2A and 2B can be closed in the usual manner, for example by arranging a fairing in the shape of an airfoil around the joint.

[0045] Figure 5 This shows how to reach the above text. Figures 4 to 7 The view shows the interior of the spacer 16 used in the section. Here, section 162 has a hexagonal interior feature 162H that mates with the hexagonal exterior feature 10H surrounding the column bolt 10. Of course, any suitable shape can be chosen for these complementary features 162H, 10H.

[0046] Figure 6 An alternative implementation of spacer 16 is shown. Here, instead of a threaded connection with multiple helical ridges, the complementary end faces of spacer components 161, 162 are shaped to form a “single screw thread” with corresponding inclined surfaces. The components maintain physical contact as long as one spacer component rotates relative to the other spacer component by no more than one full rotation. In this way, this arrangement of spacers can effectively load the opposing faces of the transition elements as explained above.

[0047] Figure 7 Another implementation of spacer 16 is shown. Here, components of spacer 16 are connected via a threaded interface as described above. In this exemplary embodiment, a segment of the spacer is formed to include gear teeth or sprocket teeth 16C around its outer circumference. During fastening of the connector assembly, the chain W3 of the fastening assembly (e.g., a tool with a motor-driven sprocket) is positioned around the sprocket teeth 16C and actuated to rotate the spacer segment relative to another spacer segment. Of course, a belt drive arrangement can be used instead of the chain drive shown here.

[0048] Figure 8 This diagram illustrates how the joint between segments 2A and 2B of a wind turbine rotor blade can be achieved using existing techniques. Here, the connector assembly 5 includes a spacer 50 in the form of a hollow block or "bathtub," shaped to receive the outer ends of two stud bolts 51 and 52. The other ends of the stud bolts are screwed into threaded inserts in the transitions of the rotor blade segments 2A and 2B. The spacer 50 must be large enough to allow tools to rotate the stud bolts. This dimensional requirement limits the number of connectors that can be deployed and results in a relatively large separation D5 between adjacent connectors, necessitating a correspondingly wide transition 22.

[0049] While the invention has been disclosed by way of preferred embodiments and variations thereof, it will be understood that many additional modifications and variations may be made thereto without departing from the scope of the invention. For clarity, it should be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.

Claims

1. A connector assembly (1) for connecting two components (2A, 2B), comprising: - a stud bolt (10) comprising a shank (10S) and a threaded portion (10T) at each end of the shank (10S); - a first threaded insert (14A, 14B) for embedding in a component (2A), adapted to engage with a first threaded portion (10T) of the stud bolt (10); - a second threaded insert (14A, 14B) for embedding in another component (2B), adapted to engage with a second threaded portion (10T) of the stud bolt (10); and - a spacer (16) dimensioned to enclose the shank (10S) of the stud bolt (10), and comprising length adjustment means (16T) for adjusting the length of the spacer (16) between an initial length (Lo) and a maximum extended length (LI). The spacer (16) comprises a plurality of surface features (161F, 162F, 16C) for engaging with spacer length adjustment means (W1, W2).

2. The connector assembly of the preceding claim, wherein, A portion of the stud shank (10S) comprises a feature (10H) having a polygonal cross-sectional shape, and the spacer (16) comprises a complementary internal feature (162H) shaped to engage with the polygonal shank feature (10H).

3. The connector assembly of any of the preceding claims, wherein, The spacer (16) comprises a first tubular segment (161) and a second tubular segment (162), and wherein the length adjustment means comprises a threaded interface (16T) between the tubular segments (161, 162).

4. The connector assembly of any of the preceding claims, wherein, First surface features (161F) are formed around the first tubular segment (161) and are shaped to engage with a tool (W1) for rotating the first tubular segment (161) relative to the second tubular segment (162).

5. The connector assembly of any of the preceding claims, wherein, Second surface features (162F) are formed around the second tubular segment (162) and are shaped to engage with a tool (W2) that prevents rotation of the second tubular segment (162).

6. The connector assembly of claim 4 or 5, wherein, The surface features (161F, 162F) are offset from the respective spacer ends by different lengths (161D, 162D).

7. The connector assembly of any of claims 4-6, wherein, The spacer (16) comprises segments (161, 162) of unequal length.

8. The connector assembly of any of the preceding claims, wherein, 9. A wind turbine rotor blade comprising a first rotor blade segment (2A) and a second rotor blade segment (2B), and a plurality of connector assemblies (1) according to any one of claims 1 to 8, arranged to connect the first rotor blade segment (2A) to the second rotor blade segment (2B).

10. A wind turbine rotor blade according to any one of the preceding claims, comprising a staggered arrangement of spacers (16). For each connector assembly (1), 11. A wind turbine rotor blade according to claim 9 or 10, wherein, - the first threaded insert (14A) is embedded in the first rotor blade segment (2A), and - the second threaded insert (14B) is embedded in the second rotor blade segment (2B); and wherein - the longitudinal axes of the threaded inserts (14A, 14B) are collinear. ​ 12. A wind turbine rotor blade according to any one of claims 8 to 10, wherein, The adjacent spacers (16) are separated by a gap of at most 10 mm.

13. A method of connecting a first wind turbine rotor blade segment (2A) to a second wind turbine rotor blade segment (2B) with a plurality of connector assemblies (1) according to any one of claims 1 to 8, the method comprising the steps of: - embedding the first and second threaded inserts (14A, 14B) of each connector assembly (1) co-linearly in the rotor blade segments (2A, 2B); - placing an adjustable length spacer (16) on the shank (10S) of each stud (10); - turning one end of each stud (10) into the first threaded insert (14A) and the other end of the stud (10) into the corresponding second threaded insert (14B); and - extending the length of the spacer (16) as needed to apply a pre-tension to the stud (10).

14. The method of claim 13, wherein, The step of turning the stud (10) into the second threaded insert (14B) is achieved by rotation of the corresponding spacer (16).

15. The method of claim 13 or 14, wherein, The step of extending the length of the spacer (16) comprises the steps of deploying a first tool (W1) to effect rotation of the first spacer component (161) and deploying a second tool (W2) to prevent rotation of the second spacer component (162).

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