Patent Publication Number: US-2019193304-A1

Title: Mould for a wind turbine blade and method of assembling same

Description:
TECHNICAL FIELD 
     The present invention relates generally to wind turbines. More particularly it relates to a mould half having a modular mould shell for manufacturing wind turbine blades. It also relates to a method for adjusting or assembling the modular mould shell so as to have a smooth transition across the interface of adjacent mould shell sections. 
     BACKGROUND 
     The typical modern wind turbine includes a tower that supports a nacelle at an upper end thereof. A rotor having a central hub and one or more blades is coupled to the nacelle and converts the kinetic energy of the wind into mechanical energy, usually in the form of a rotating main shaft. The nacelle includes various components, such as a drive train and a generator, that convert the mechanical energy from the rotor into electrical energy. The radius of the rotor influences the performance of the wind turbine. For example, a wind turbine with an increased radius may deliver power even in lighter wind conditions. Additionally, a wind turbine with an increased radius may deliver more power due to the increased energy within the area defined by the radius. The radius of the rotor is substantially determined by the length of the wind turbine blades. Accordingly, the size of wind turbine blades has dramatically increased over the years in order to improve wind turbine efficiencies. By way of example, wind turbine blades as long as 90 m are currently in production and the size of the blades is expected to further increase in the future. As the blades are a major aspect and cost of wind turbine construction, much effort has been directed toward the efficient manufacturing of the blades. 
     According to one conventional process, a wind turbine blade is manufactured by disposing structural outer shell material, such as glass fiber material or carbon fiber material, into two mould halves and then injecting a binder, such as an epoxy resin, polyester resin, or other suitable material around the structural outer shell material while a vacuum system (e.g., vacuum bag) presses the structural outer shell material into each of the mould halves. In an alternate process, pre-impregnated composite material may be used which precludes injecting the material with a binder. In any event, after curing the binder about the structural outer shell material, the two halves of the wind turbine blade outer shell may be coupled to one another around a structural support member such as a web or a spar. In this regard, once the blade halves are formed in their respective moulds, the mould halves may be moved relative to each other to locate one mould half on top of the other mould half such that the edges of the two blade halves are generally aligned with each other. The mould halves may then be brought even closer together so that the edges of the blade halves may be, for example, adhesively bonded together along the leading and trailing edges of the blade, thereby completing blade construction. 
     While the manufacturing method described above is generally successful for its intended purpose, manufacturers have realized certain limitations to the conventional manufacturing method. More particularly, as the size of wind turbine blades has continued to increase, the size of the moulds used to make the blades has correspondingly increased. Due to the increased size of the moulds, the ability to transport the moulds to desired locations is severely limited. Accordingly, production facilities for full size moulds may have to be established at or near the production facilities for the blades, which also suffer from limitations in road transportation due to their increased size. 
     Various solutions to these issues have been proposed. By way of example, one solution is to mould the rotor blade in parts arranged across the length of the blade. In this approach, the mould is split into mould parts and in each mould part, a section of the blade is formed. The completed sections are then coupled end-to-end to form the full length blade. In another approach, a modular mould system which is comprised of a number of mould sections is used to form the blade. A junction of one mould section and an adjacent mould section is formed by a flexible end segment. The end segment is configured to substantially match the contour of the adjacent mould section such that there is no discontinuity in the blade surface across the junction. 
     While such techniques have been generally successful for their intended purpose, blade manufactures continue to strive to improve upon current manufacturing devices and methodologies. More particularly, blade manufacturers continue to strive to improve the transition between sections of a modular mould system for wind turbine blades. 
     SUMMARY 
     A method of assembling a mould for forming a wind turbine blade includes providing a mould half having a mould shell defining a mould surface, the mould shell having at least a first mould shell section and a second mould shell section; positioning the at least first mould shell section and the at least second mould shell section adjacent one another so that connecting ends of each of the first and second mould shell sections confront each other along an interface; and wherein the first mould shell section includes a first flange adjacent the connecting end and extending away from the mould surface of the first mould shell section, the second mould shell section includes a second flange adjacent the connecting end and extending away from the mould surface of the second mould shell section. The method including adjusting the relative positions of the first and second mould shell sections to that the mould surface across the interface is substantially flush; and with the mould surface across the interface substantially flush, securing the relative positions of the first and second mould shell sections in order to maintain a smooth transition across the interface. 
     In accordance with an aspect of the invention, at least one adjustment device may be mounted to the first and second mould shell sections adjacent the interface, wherein the at least one adjustment device is configured to adjust the relative positions of the first and second mould shell sections. Mounting the at least one adjustment device to the first and second mould shell sections includes mounting a first bracket to one of the first and second mould shell sections; mounting a second bracket to the other of the first and second mould shell sections; and coupling an adjustment connector to each of the first and second brackets, wherein the adjustment connector includes at least one adjustment actuator. Adjusting the relative positions of the first and second mould shell sections may thereby include operating the adjustment actuator to provide movement of the first and second mould shell sections relative to each other. The adjustment actuator may exhibit an adjustment path defining a direction of an adjustment movement between the first and second mould shell sections. Preferably, the adjustment direction may extend in a thickness direction of the mould, which is to say, a direction relative to the mould surface corresponding to a thickness direction of a blade or blade part moulded therein. In further aspects of the invention, the adjustment connector may comprise a connecting rod. Preferably, the adjustment actuator may comprise a rotatable member, preferably associated with the connecting rod. In one embodiment, coupling a connecting rod to the first and second brackets includes inserting a shaft of the connection rod through an opening in the first bracket; disposing the first bracket between a first pair of rotatable members on the shaft; inserting the shaft through an opening in the second bracket; and disposing the second bracket between a second pair of rotatable members on the shaft. The shaft may be a threaded shaft. 
     In one embodiment, mounting the first and second brackets may further include providing a pair of L-shaped brackets, each having a first leg and a second leg extending therefrom; coupling the first leg of one bracket to one of the first and second mould shell sections; coupling the first leg of the other bracket to the other of the first and second mould shell sections; and orienting the second leg of each bracket in the same direction such that the second legs overlap with each other in a longitudinal direction of the mould half. 
     Advantageously, the adjustment connector or connecting rod preferably extends between the second legs of the pair of brackets. In one embodiment, the first leg of the one bracket is coupled to one of the first and second flanges and the first leg of the other bracket is coupled to the other of the first and second flanges. 
     The first bracket, second bracket, and adjustment connector may be arranged such that an adjustment path of the adjustment connector is oriented in a substantially thickness direction of the mould half, and relative movement between the first and second mould shell sections is in the substantially thickness direction of the mould half, which thickness direction may in some cases may correspond to a vertical direction. Preferably, in the case of an adjustment connector comprising a connector rod, the connector rod may extend in a thickness direction of the mould. The first bracket, second bracket, and connecting rod may also be arranged such that the connecting rod is positioned only on one side of the interface, when considered in the longitudinal direction of a blade formed in the relevant mould-half. Hence, according to an aspect of the invention, the method may further comprise arranging the first bracket, second bracket, and adjustable connector such that the adjustable connector is positioned only on one side of the interface. 
     A method of manufacturing a wind turbine blade includes providing a first mould half assembled according to that described above, and placing fibre and a resin in the mould shell of the first mould half to form a first shell half of the wind turbine blade. The method may further include providing a second mould half and placing fibre and a resin in a mould shell of the second mould half to form a second shell half of the wind turbine blade. In one embodiment, the first and second mould halves are movably coupled together and the method further includes moving the first and second mould halves relative to each other such that one mould half is on the other mould half and the first and second shell halves of the wind turbine blade confront each other, and coupling the first and second shell halves together to form the wind turbine blade. 
     In accordance with aspects of the method, the securing step may include providing one or a plurality of holes in one of the first and second mould shell sections adjacent the interface; using the one or plurality of holes in the one of the first and second mould shell sections as a guide for forming a corresponding one or plurality of holes in the other of the first and second mould shell sections, such that the one or plurality of holes and the corresponding one or plurality of holes are in substantial alignment with each other; and engaging a fastener with each of the substantially aligned holes and corresponding holes in the first and second mould shell sections. In one embodiment, forming the corresponding holes may include inserting a drill element into a hole of the one of the first and second mould shell sections; drilling a corresponding hole in the other of the first and second mould shell sections using the hole as a guide; and repeating these steps for each or any of the remaining holes in the first and second mould shell sections. A plurality of pre-formed holes may be provided in one of the first and second flanges and the corresponding plurality of holes may be subsequently formed in the other of the first and second flanges, after the said adjustment step. The holes and corresponding holes may be oriented so as to be substantially aligned in a longitudinal direction of the mould half. 
     A mould half for forming a wind turbine blade includes a mould shell defining a mould surface, the mould shell including at least a first mould shell section and a second mould shell section, each of the first and second mould shell sections having a connecting end which confront each other along an interface. The first mould shell section includes a first flange adjacent the connecting end and extending away from the mould surface of the first mould shell section, and the second mould shell section includes a second flange adjacent the connecting end and extending away from the mould surface of the second mould shell section. Preferably, the first bracket of the adjustment device is coupled to one of the first and second flanges and the second bracket is coupled to the other of the first and second flanges. At least one adjustment device is positioned adjacent the interface and coupled to both the first and second mould shell sections, wherein the at least one adjustment device is configured move the first and second mould shell sections relative to each other. The at least one adjustment device includes a first bracket coupled to one of the first and second mould shell sections; a second bracket coupled to the other of the first and second mould shell sections; and an adjustment connector coupled to each of the first and second brackets and including at least one adjustment actuator. Operation of the at least one adjustment actuator provides relative movement between the first and second mould shell sections. The first bracket, second bracket, and adjustment connector are preferably arranged such that the adjustment connector is positioned only on one side of the interface. In this regard, at least one of the brackets extends across the interface to define an overlap region between the first and second brackets, wherein the adjustment connector is coupled to the first and second brackets in the overlap region. Alternatively or additionally, the first bracket, second bracket, and adjustment connector may be arranged such that an adjustment path of the adjustment connector is oriented in a substantially vertical direction. Preferably, the first and second brackets comprise L-shaped brackets. Preferably, the adjustment connector includes a connecting rod. Preferably, an adjustment connector such as a connecting rod may include a threaded shaft. Preferably, the at least one adjustment actuator may comprise a rotatable member. Preferably, a rotatable member may include a first pair of nuts and a second pair of nuts. In embodiments, the adjustment connector may comprise a connecting rod. In embodiments the adjustment actuator may comprise a rotatable member, preferably associated with a connecting rod. 
     Preferably, the first bracket is coupled to one of the first and second flanges and the second bracket is coupled to the other of the first and second flanges. In one embodiment, the first and second brackets include L-shaped brackets, the adjustment connector includes a connecting rod, preferably includes a threaded shaft, and the at least one rotatable member includes a first pair of nuts and a second pair of nuts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various additional features and advantages of the invention will become more apparent to those of ordinary skill in the art upon review of the following detailed description of one or more illustrative embodiments taken in conjunction with the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the general description given above and the detailed description given below, serve to explain the one or more embodiments of the invention. 
         FIG. 1  is a diagrammatic perspective view of a wind turbine having a blade formed by a moulding apparatus in accordance with one embodiment of the invention; 
         FIG. 2  is a perspective view of a wind turbine blade shown in  FIG. 1 ; 
         FIG. 2A  is a cross-sectional view of the wind turbine blade shown in  FIG. 2 ; 
         FIG. 3  is a partial perspective view of a moulding apparatus for forming wind turbine blades; 
         FIG. 4  is a partial perspective view of an interface between adjacent mould shell sections of a mould half in accordance with an embodiment of the invention; 
         FIG. 5A  is a cross-sectional view of the mould shell sections of  FIG. 4  illustrating an adjustment device and with the adjacent mould shell sections out of alignment; 
         FIG. 5B  is another cross-sectional view of the mould shell sections of  FIG. 4  with the mould shell sections in alignment; and 
         FIG. 5C  is another cross-sectional view of the mould shell section of  FIG. 4  with the mould shell sections secured together. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the figures, and to  FIG. 1  in particular, an exemplary horizontal-axis wind turbine  10  generally includes a tower  12 , a nacelle  14  disposed at the apex of the tower  12 , and a rotor  16  operatively coupled to a generator housed inside the nacelle  14 . In addition to the generator, the nacelle  14  houses miscellaneous components required for converting wind energy into electrical energy and various components needed to operate, control, and optimize the performance of the wind turbine  10 . The tower  12  supports the load presented by the nacelle  14 , the rotor  16 , and other components of the wind turbine  10  that are housed inside the nacelle  14 . The tower  12  further operates to elevate the nacelle  14  and rotor  16  to a height above ground level or sea level, as may be the case, at which faster moving air currents of lower turbulence are typically found. 
     The rotor  16  of the wind turbine  10  serves as the prime mover for the electromechanical system. Wind exceeding a minimum level will activate the rotor  16  and cause rotation in a substantially perpendicular direction to the wind direction. The rotor  16  of wind turbine  10  includes a central hub  18  and a plurality of blades  20  that project outwardly from the central hub  18  at locations circumferentially distributed thereabout. While the exemplary rotor  16  shown herein includes three blades  20 , various alternative quantities of blades may be provided. The blades  20  are configured to interact with the passing air flow to produce lift that causes the rotor  16  to spin generally within a plane defined by the blades  20 . 
     The wind turbine  10  may be included among a collection of similar wind turbines belonging to a wind farm or wind park that serves as a power generating plant connected by transmission lines with a power grid, such as a three-phase alternating current (AC) power grid. The power grid generally consists of a network of power stations, transmission circuits, and substations coupled by a network of transmission lines that transmit the power to loads in the form of end users and other customers of electrical utilities. Under normal circumstances, the electrical power is supplied from the generator  18  to the power grid as known to a person having ordinary skill in the art. 
     With reference to  FIGS. 2 and 2A , a wind turbine blade  20  is an elongate structure having, in an exemplary embodiment, an outer shell  22  disposed about an inner support element or spar  24 . The outer shell  22  may be optimally shaped to give the blade  20  the desired aerodynamic properties to generate lift, while the spar  24  provides the structural aspects (e.g., strength, stiffness, etc.) to blade  20 . The elongate blade  20  includes a root end  26  which is coupled to the central hub  18  when mounted to rotor  16 , and a tip end  28  longitudinally opposite to root end  26 . As discussed above, the outer shell  22  includes a first, upper shell half  30  on the suction side of the blade  20 , and a second, lower shell half  32  on the pressure side of the blade  20 , the upper and lower shell halves  30 ,  32  being coupled together along a leading edge  34  and a trailing edge  36  located opposite one another across a width of the blade  20 . 
     In accordance with an exemplary embodiment of the invention and as illustrated in  FIG. 3 , a moulding apparatus  40  for forming rotor blades, such as blades  20  described above, includes a first mould half  42  and a second mould half  44  positioned adjacent to each other. The first mould half  42  is configured to be used to at least partially form the first shell half  30  of the blade  20  and the second mould half  44  is configured to be used to at least partially form the second shell half  32  of the blade  20 . To this end, the first mould half  42  includes a first contoured mould surface  46  generally corresponding to a negative of the contoured surface of the first shell half  30 . Similarly, the second mould half  44  includes a second contoured mould surface  48  generally corresponding to a negative of the contoured surface of the second shell half  32 . 
     The first mould half  42  comprises a first mould shell half  50  forming the first contoured mould surface  46  and a first support structure  52  to support the first mould shell half  50 . In a similar manner, the second mould half  44  includes a second mould shell half  54  forming the second contoured mould surface  48  and a second support structure  56  to support the second mould shell half  54 . In an exemplary embodiment, the first and second mould shell halves  50 ,  54  are formed from a fibre-reinforced composite, such as a fibre-reinforced composite formed from resin, carbon fibre and/or fibreglass. Additionally, in an exemplary embodiment, the first and second support structures  52 ,  54  may be formed by metal frames such as steel frames. It should be recognized, however, that in various alternative embodiments other materials may be used to form the mould shell halves  50 ,  54  and/or the support structures  52 ,  54 . 
     In accordance with an aspect of the invention, and as illustrated in  FIG. 3 , the moulding apparatus  40  may have a modular or split design wherein the first and second mould halves  42 ,  44  include two or more mould half sections longitudinally arranged which, when coupled together at a mating junction, form the complete mould halves  42 ,  44 . As noted above, the modular design of the moulding apparatus  40  provides certain benefits in transporting the moulds and ancillary devices for manufacturing wind turbine blades. 
     By way of example, in an exemplary embodiment the first mould half  42  includes a root mould half section  58  and a tip mould half section  60  which are configured to mate at a first junction  62 . In a similar manner, the second mould half  44  includes a root mould half section  64  and a tip mould half section  66  which mate at a second junction  68 . As a result of the modularity, the first mould shell half  50  includes a root mould shell section  70  and a tip mould shell section  72  which mate at a first mould shell interface  74 . The first support structure  52  may also include a root support structure  76  for supporting the root mould shell section  70  and a tip support structure  78  for supporting the tip mould shell section  72 . In a similar manner, the second mould shell half  54  includes a root mould shell section  80  and a tip mould shell section  82  which mate at a second mould shell interface  84 . The second support structure  56  may also include a root support structure  86  for supporting the root mould shell section  80  and a tip support structure  88  for supporting the tip mould shell section  82 . In an exemplary embodiment, the first and second mould shell interfaces  74 ,  84  extend transversely in relation to the longitudinal direction of the mould assembly  40 , such as, for example, in a substantially perpendicular (relative to the longitudinal direction) or chord-wise direction of a blade  20  formed in the mould assembly  40 . Other directions, however, may be possible. 
     While the modularity of the first and second mould halves  42 ,  44  has been described above as including two sections, it should be recognized that the mould halves  42 ,  44  may be formed from more than two sections, such as three or four sections. Moreover, while both mould halves  42 ,  44  have been described as each having the same number of sections, it should be realized that the mould halves  42 ,  44  may have a different number of sections that form the respective mould halves. Furthermore, in the embodiment described above, each mould shell section (e.g., mould shell sections  70 ,  72 ) was associated with a respective support structure section (e.g., support structure sections  76 ,  78 ). However, in alternative embodiments, there may be multiple mould shell sections on a single support structure section. Thus, the invention is not limited to the arrangement illustrated in the figures, but various alternative arrangements will be appreciated by those of ordinary skill in the art. 
     In the illustrated embodiment, one of the first and second mould halves  42 ,  44  is movable relative to the other such that first and second mould halves  42 ,  44  may be used to couple the first and second blade shell halves  30 ,  32  to each other and to form the outer shell  22  of the blade  20 . By way of example, the moulding apparatus  40  may have a clamshell configuration having a fixed mould half and a movable mould half movable relative to the fixed mould half so as to come to rest on top of the fixed mould half. For example, the first mould half  42  may be configured to be fixed to ground and the second mould half  44  may be configured to be movable relative to the first mould half  52  and relative to ground. The opposite arrangement is also possible. 
     With such a clamshell configuration, the second mould half  44  may be movable relative to the first mould half  42  between an opened position, as illustrated in  FIG. 3 , and a closed position (not shown) with the second mould half  44  resting on the first mould half  42  such that the first and second contoured mould surfaces  46 ,  48  form a cavity between the first and second mould halves  42 ,  44 . For example, the moulding apparatus  40  may include a turner assembly  90  to effectuate movement of the second mould half  44  relative to the first mould half  42 . The turner assembly  90  may be positioned between the first and second mould halves  42 ,  44  when in the opened position and includes a hinge or pivot device such that the second mould half  44  is configured to rotate about a pivot axis when moved toward the closed position. In the opened position, the contoured surfaces  46 ,  48  of the first and second mould halves  42 ,  44 , respectively, are exposed such that the blade shell halves  30 ,  32  may be formed therein. This may be achieved, for example, by placing fiber and a resin in the first and second mould shell halves  50 ,  52 . In the closed position with the second mould half  44  positioned on top of the first mould half  42 , respective pairs of confronting edges of the first and second blade shell halves  30 ,  32  may be generally aligned and in contact or near contact with each other so as to be coupled together to form the leading and trailing edges  34 ,  36  of the blade  20 . 
     While the modular design of the moulding apparatus  40  provides certain benefits, care must be taken to ensure that those benefits are not offset by the introduction of other undesirable effects in the manufacturing process. For example, as can be appreciated by those of ordinary skill in the art, the performance of wind turbine blades is sensitive to defects, disruptions, discontinuities, etc., in the surface of the blades over which air flows. Accordingly, when implementing a modular mould design, it is important that the transition between the mould sections, and in particular the mould surfaces, be smooth and substantially without disruption so that no defects result in the surface of the blade formed in the mould. 
     To facilitate the prevention or minimization of defects at the interface between mould shell sections, the moulding apparatus includes one or more adjustment devices that provide relative movement between adjacent mould shell sections. By manipulating the adjustment devices, the moulding surfaces of adjacent moulding sections may be adjusted so as to be substantially flush such that defects in the surface of the wind turbine blade at the interface between the adjacent sections may be avoided. 
     In this regard and as best illustrated in  FIG. 4 , the moulding apparatus  40  includes one or more adjustment devices  100  adjacent the interface  74  between the root mould shell section  70  and the tip mould shell section  72  of the first mould half  42 . Although not shown, adjustment devices  100  may also be provided adjacent the interface  84  between the root mould shell section  80  and the tip mould shell section  82  of the second mould half  44 . The description and operation of the adjustment devices  100  will be described with reference to interface  74  in the first mould half  42 . It should be realized, however, that the description may also apply to the adjustment devices for the second mould half  44 . 
     The interface  74  is formed by the juxtaposition of a connecting end  102  of the root mould shell section  70  and a connecting end  104  of the tip mould shell section  72 . The connecting end  102  of the root mould shell section  70  includes a depending flange  106  which extends away from the moulding surface  46  of the root mould shell section  70 . By way of example, the depending flange  106  may extend away from the moulding surface  46  in a substantially perpendicular manner relative to the moulding surface  46 , e.g. corresponding to a thickness direction of a blade when present in the mould. In a similar manner, the connecting end  104  of the tip mould shell section  72  includes a depending flange  108  which extends away from the moulding surface  46  of the tip mould shell section  72 . By way of example, the depending flange  108  may extend away from the moulding surface  46  in a substantially perpendicular manner, e.g. corresponding to a thickness direction of a blade when present in the mould. The flanges  106 ,  108  are arranged such that when the connecting ends  102 ,  104  are brought together, the flanges  106 ,  108  confront each other and are in contact or near contact with each other. 
     Broadly speaking, the adjustment device includes a first structural member coupled to one of the mould shell sections, a second structural member coupled to the other mould shell section, and a connecting rod extending between the two structural members. At least a portion of the connecting rod is movable or actuatable such that the position of the two structural members relative to each other may be varied. In an exemplary embodiment, the adjustment device  100  includes a first bracket  110  having a connecting end coupled to the flange  106  of the root mould shell section  70  and a free end, and a second bracket  112  having a connecting end coupled to the flange  108  of the tip mould shell section  72 . As illustrated in  FIG. 4 , in an exemplary embodiment, the first and second brackets  110 ,  112  may include L-shaped brackets having a first leg  114  substantially parallel to the flanges  106 ,  108  to which they are coupled, and a second leg  116  extending therefrom in, for example, a substantially perpendicular manner and including the free end. The first legs  114  of the brackets  110 ,  112  may be coupled to their respective flanges  106 ,  108  by various fasteners such as screws, rivets, bolts, etc. Other means of connecting the brackets  110 ,  112  to the flanges  106 ,  108  may also be used, such as by means of adhesive e.g. epoxy-type adhesive. In a preferred mode, both a fastener and a layer of adhesive may be used between a first leg  114  of a bracket  110  and a flange  106 ,  108  of a mould shell to secure these elements together. 
     The first and second brackets  110 ,  112  are coupled to their respective flanges  106 ,  108  such that the second legs  116  thereof extend in substantially the same direction (e.g., toward the root end or the tip end of the moulding apparatus  40 ). In this way, at least a portion of the brackets  110 ,  112 , such as the second legs  116  thereof, overlap with each other in, for example, a longitudinal direction L of the mould half  42 , as illustrated in  FIG. 4 . In this regard, the second leg  116  of the first bracket  110  extends across the interface  74  to provide an overlapping region of the first and second brackets  110 ,  112 . Additionally, the brackets  110 ,  112  are arranged such that the overlapping region (e.g., second legs  116 ) is substantially aligned in a width direction W of the mould half  42  (corresponding to a chordwise direction of a blade made in said mould), and are offset from one another in a height direction H of the mould half  42  (corresponding to a thickness direction of a blade made in said mould). The adjustment device  100  further includes an adjustment connector  118  extending between the first and second brackets  110 ,  112 , and more particularly between the second legs  116  of the brackets (e.g., the overlapping region). The adjustment connector  118  includes one or more adjustment actuators  120  such that when the one or more adjustment actuators  120  are rotated, the relative position of the mould shell sections  70 ,  72  is varied. The adjustment connector  118  is shown here by way of example as a connecting rod. The connecting rod includes one or more adjustment actuators  120  in the form a one or more rotatable members, such that when the one or more rotatable members are rotated, the relative position of the mould shell sections  70 ,  72  is varied. In the present example, an adjustment path of the adjustment connector extends in a thickness direction H of the mould assembly. 
     In an exemplary embodiment, the connecting rod of the adjustment connector  118  may be or may include a threaded bolt or shaft  122  and the adjustment actuators  120  may include nuts  124  such as, for example, a set of four nuts. The second legs  116  of each of the brackets  110 ,  112  include an oblong slot  126  extending generally in the length direction of the second legs  116  and configured to receive the threaded shaft  122  therethrough. Forming the slots  126  so as to have an elongate or oblong shape may facilitate assembly of the adjustment device  100 . As illustrated, in an exemplary embodiment an adjustment actuator  120 , shown in the form of a first pair of nuts  124 , may be associated with the first bracket  110  and a second adjustment actuator  120 , shown in the form of a second pair of nuts  124 , may be associated with the second bracket  112 . More particularly, the first adjustment actuator  120  may be disposed on opposed sides (e.g., an upper and lower side) of the second leg  116  of the first bracket  110  and the second adjustment actuator  120  may be disposed on opposed sides of the second leg  116  of the second bracket  112 . By manipulating the adjustment actuator  120 , the relative position of the root mould shell section  70  and the tip mould shell section  72  of the first mould half  42  may be selectively varied. In particular the relative position of the said mould shell sections  70 ,  72  may be varied in the direction H of an adjustment path of the adjustment connector  118 . 
     In an exemplary embodiment, the first bracket  110 , second bracket  112 , and the adjustment connector  118  may be arranged such that the adjustment connector  118  extends in a height direction of the mould half  42 , corresponding in particular to a thickness direction of a blade in the mould. Accordingly, the relative position of the mould shell sections  70 ,  72  may be varied generally in a height direction of the mould half  42  (see  FIG. 4 ), i.e. in a thickness direction of the mould assembly. In one embodiment, the height direction may correspond to a substantially vertical direction of the mould half  42 . Other directions, however, may also be selected, such as, for example, in a range of about ±10° about the thickness direction H. Such an arrangement minimizes bending stresses in the adjustment connector  118  and allows the bending stresses to be accommodated by the brackets  110 ,  112  instead of by the adjustment connector  118 . Furthermore, in an exemplary embodiment, the first bracket  110 , second bracket  112 , and the adjustment connector  118  may be arranged such that the adjustment connector  118 , such as a connecting rod, is positioned only on one side of the interface  74 , and thus does not extend across the interface  74 . The adjustment connector  118  may be configured as a rod or any type of shank or shaft or grooved shaft or toothed track or other suitable element, e.g. an element providing easy incremental adjustability along a length thereof. In particular, it is desirable for an adjustment connector  118  to enable a discrete adjustment of the adjustment assembly. 
       FIGS. 5A-5C  schematically illustrate the assembly of mould half  42 , including the use of adjustment device  100  to align the mould shell sections  70 ,  72 . The relative thicknesses of the mould shell and the brackets  110 ,  112  may not be shown to scale. In particular, the mould shell may be appreciably thicker than illustrated, relative to the bracket thickness. For purposes of discussion, in  FIG. 5A  the mould shell sections  70 ,  72  are not in alignment with each other and a discontinuity exists at the interface  74 . Accordingly, to provide a smooth transition, an adjustment must be made between the sections  70 ,  72 . The adjustment can be accomplished in several ways. For example, in one embodiment, the root mould shell section  70  may be held stationary and the tip mould shell section  72  may be moved, such as in the direction of arrow A. In this regard, the upper and lower nuts  124  shown by way of example and associated with the second bracket  112  may be loosened such that the tip mould shell section  72  may be moved so that the sections  70 ,  72  are substantially flush and have a smooth transition at the interface  74 . When the mould shell section  72  is moved to such a location, the nuts  124  may be tightened so as to securely clamp the second leg  116  of the second bracket  112  therebetween and fix the relative position of the mould shell sections. 
     In an alternative embodiment, the tip mould shell section  72  may be held stationary and the root mould shell section  70  may be moved, such as in the direction of arrow B. In this regard, the upper and lower nuts  124  associated with the first bracket  110  may be loosened such that the root mould shell section  70  may be moved so that the sections  70 ,  72  are substantially flush and have a smooth transition at the interface  74 . When the mould shell section  70  is moved to such a location, the nuts  124  may be tightened so as to securely clamp the second leg  116  of the first bracket  110  therebetween and fix the relative position of the mould shell sections. 
     In yet another alternative embodiment, both mould shell sections  70 ,  72  may be moved toward one another so as to provide a smooth transition at the interface  74 . In this regard, the upper and lower nuts  124  associated with each of the first and second brackets  110 ,  112  may be loosened, the sections  70 ,  72  appropriately positioned to be substantial flush to provide a smooth transition, and the nuts  124  tightened to clamp the second legs  116  of the brackets  110 ,  112  therebetween. Those of ordinary skill in the art may recognize other alternative methodologies for utilizing the adjustment device  100  to substantially align the mould shell sections  70 ,  72  so as to provide a smooth transition at the interface  74 . As used herein, the mould sections  70 ,  72  are substantially flush when a step in the surfaces of the sections  70 ,  72  at the interface  74  is less than about 3 mm or less than about 2 mm, preferably less than 1 mm, still preferably less than 0.5 mm. As already indicated herein, the adjustment connector  118  and adjustment actuator  120  may be provided in any appropriate form, with the illustrated threaded shaft and the nuts  124  being but one example. 
     When the mould shell sections  70 ,  72  are properly aligned, the relative position of the shell sections  70 ,  72  may be additionally secured to one another (i.e., by more than just the adjustment devices  100 ). In a conventional approach, each of the flanges  106 ,  108  may include a plurality of pre-formed holes configured to receive a fastener for securing the mould shell sections together. However, if the alignment of the shell sections is not precisely determined, and adjustment of one or both of the mould shell sections is required to produce a smooth transition at the interface, the holes in the flanges  106 ,  108  may not be in alignment, and thus may not be able to receive a fastener. Thus, in accordance with an aspect of the present invention, holes in at least one of the flanges may not be formed until the mould shell sections have been properly aligned and a smooth transition at the interface is achieved. 
     In an exemplary embodiment, for example, a plurality of holes  130  may be formed through flange  106  of the root mould shell section  70 , but no holes formed through flange  108  of the tip mould shell section  72 . By way of example, the holes  130  in flange  108  may be pre-formed, such as during manufacturing of the moulding shell section  70 . As illustrated in  FIG. 5B , after the mould shell sections  70 ,  72  have been substantially aligned to produce a smooth transition at the interface  74  using the adjustment devices  100 , corresponding holes  132  may be formed through flange  108 . In one aspect of the invention, the holes  130  in flange  106  may be used as guide or pilot holes (e.g., a template) for forming the holes  132  in the flange  108 . Such a process ensures that the holes  130 ,  132  are in substantial alignment with each other so as to receive a fastener. In this regard, a drill element  134 , such as a drill bit, may be inserted into a hole  130  and sufficiently driven in order to form the corresponding hole  132 . This process may be repeated for each of the plurality of holes  130  in the flange  106 . 
     With the holes  130 ,  132  in respective flanges  108 ,  106  in substantial alignment, a fastener  136  may be inserted through the holes  130 ,  132  to secure the position of the mould shell sections  70 ,  72  relative to each other. In one embodiment, the fastener  136  may be a nut and bolt. Other fasteners, such as screws, rivets, etc., may alternatively be used. While the figures illustrated holes  130  in flange  106  and the subsequent formation of holes  132  in flange  108  using holes  130  as pilot holes, it should be recognized that in an alternative embodiment the holes may be formed in flange  108  and those holes used as pilot holes for the formation of holes in flange  106 . In still a further embodiment, some pilot holes may be formed in flange  106  and some pilot holes formed in flange  108 . In any event, in an exemplary embodiment, the holes  130 ,  132  may be substantially aligned in a longitudinal direction of the mould half  42 . 
     The number of adjustment devices  100  along the length of the flanges  106 ,  108  may be varied. Thus, while five adjustment devices  100  are illustrated in  FIG. 4 , for example, more or less devices may be used and remain within the scope of the invention. Additionally, the number of holes  130 ,  132  and fasteners  136  for securing the position of the mould shell sections  70 ,  72  relative to each other may also be varied. By way of example and without limitation, anywhere from 10-40 fasteners  136  may be used although in some cases higher or lower numbers may be used. This number, however, depends on the size of the moulds and may be varied accordingly to achieve a secure connection between the mould shell sections  70 ,  72 . 
     While the description provided above was directed to the adjustable coupling of the mould shell sections  70 ,  72  of the first mould half  42 , it should be recognized that a similar arrangement and process may be used to adjustably couple mould shell sections  80 ,  82  of the second mould half  44 . Additionally, it should be recognized that while the mould halves  42 ,  44  were described as having only two sections, each mould half  42 ,  44  may have more than two sections. In such an embodiment, the sections may be adjustably coupled together in a manner similar to that described above. Furthermore, a wind turbine blade manufactured using the mould shell segments described herein may be a portion a wind turbine blade, in particular, a lengthwise portion thereof such as a longitudinal segment of a blade. 
     While the present invention has been illustrated by the description of various embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept.