Abstract:
The invention relates to a lifting equipment for handling a wind turbine component in connection with lifting means. The equipment comprises a base frame with at least one attachment area, and at least two attachment points for said wind turbine component. The at least one of said attachment points are adjustable mounted in relation to said base frame. 
     The invention also relates to a method for handling a wind turbine component.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of pending International patent application PCT/DK2007/000313 filed on Jun. 27, 2007 which designates the United States and claims priority from Danish patent application PA 2006 00893 filed on Jun. 30, 2006, the content of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to lifting equipment for handling a wind turbine component and a method for handling a wind turbine component. 
       BACKGROUND OF THE INVENTION 
       [0003]    Transportation and lifting of the different sections of a wind turbine is always a challenge and especially wind towers or tower segments are quite unmanageable. The shape and dimensions of the units vary from unit to unit e.g. because of the conical shape of wind towers. 
         [0004]    Usually the tower segments of a wind turbine are mounted with lifting equipment at the tower flanges. 
         [0005]    EP patent no. EP-B 1 303 447 discloses an example of a known lifting system wherein an outline of a gripping device for a wind turbine tower segment. The gripping device can be fastened to the tower segment in a certain position on the flanges, by screw connections through holes adapted to said flanges. The holes in the gripping device are arranged according to the holes in the flanges of the tower section. 
         [0006]    A problem with the solution of the above mentioned EP-patent is that due to the unlike attachment points on the different segments, different unique gripping devices has to be produced and used when erecting a wind turbine. Consequently the erection process will be prolonged and more expensive than necessary. 
         [0007]    An object of the present invention is to describe a lifting device without the mentioned disadvantages and especially does not involve changing operations of lifting equipment during erection of a wind turbine. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention provides lifting equipment for handling wind turbine components in connection with lifting means, said lifting equipment comprising 
         [0009]    a base frame with at least one attachment area, and 
         [0010]    at least two attachment points for said wind turbine component 
         [0011]    where at least one of said attachment points are adjustable mounted in relation to said base frame. 
         [0012]    Hereby it is ensured that the lifting equipment can be adapted and used with a plurality of different wind turbine components where the distance and relative angle between attachment points of the components vary. 
         [0013]    In one aspect of the invention said wind turbine component is a wind turbine tower segment. Hereby it is ensured that one lifting equipment can be used with any of said tower segments including the lower segments with larger diameters and the upper segments with smaller diameters e.g. when erecting a conical wind turbine tower. Furthermore the same lifting equipment can be used when handling the different segments in connection with manufacturing and transportation. 
         [0014]    The preferred attachment points of wind turbine tower segments are the connection holes of any flange of the segments. 
         [0015]    In another aspect of the invention at least one of said attachment points comprises at least one sleeve with a through going hole which centre is dislocated from the centre of said sleeve in order to perform an eccentric movement within the area of a hole in said base frame. It is hereby ensured that the distance and angle between at least two attachment points of the lifting equipment can be adjusted to desired positions i.e. the sleeve hole may be positioned at a desired position within the area of the hole of the base frame. 
         [0016]    In another aspect of the invention the base frame comprises at least one through going hole, the area of said through going hole in the base frame being substantially larger than the area of said hole in at least one sleeve e.g. at least twice in size in relation to a hole in said at least one sleeve. Hereby it is possible to achieve a high degree of freedom to place the hole of the sleeve anywhere within the area of the hole of the base frame. 
         [0017]    In another aspect of the invention the number of sleeves is two, first and second sleeve, which are partly or totally integrated into each other or into the base frame e.g. in depressed areas of the base frame and sleeve, respectively. By integrating the sleeves into each other an enhanced stability can be ensured. Further by entering locking means thru the sleeves and base frame at the integration areas it is possible in an embodiment to lock them to each other e.g. during transportation, positioning etc. 
         [0018]    In a further aspect of the invention said first sleeve is located in a depressed area of said base frame and a second sleeve is located in a depressed area of said first sleeve opposite to the base frame. Hereby it is achieved a higher stability in especially a perpendicular direction in relation to the attachment of the wind turbine component. 
         [0019]    In an even further aspect of the invention the eccentric movement between the holes in said two sleeves and the eccentric movement between the hole in the first sleeve and the hole in the base frame allows a double eccentric movement of the hole in the second sleeve in relation to the base frame. It is hereby ensured that it is possible to place the hole in the second sleeve over any desired position within the area of the hole in the base frame which gives the maximum flexibility of the invented lifting equipment. 
         [0020]    In another aspect of the invention said first sleeve comprises a through going hole with a diameter larger than the diameter of the hole in said second sleeve and said base frame comprises a through going hole with a diameter larger than the diameter of the hole in said first sleeve. Hereby is an advantageous embodiment of the invention achieved. 
         [0021]    In another aspect of the invention at least a further attachment point comprises a mounted strut in relation to the base frame. It is hereby ensured that shear stress between the wind turbine component and the invented lifting equipment especially during the initial lifting can be handled by a non-movable part of the lifting tool. Furthermore when placing the invented lifting equipment on its location of operation e.g. on the flange of a wind turbine tower section, the steering of the lifting equipment is eased by using the fixed mounted strut as a guard-pin. 
         [0022]    In another aspect of the invention said strut in relation to the base frame is replaceable e.g. to a strut with another diameter and/or length and/or shape such as triangular or circular. Hereby it is ensured that an optimal elaborated strut can be used and adapted to the invented lifting equipment dependent of e.g. the elaboration of the attachment point or attachment area. 
         [0023]    In another aspect of the invention the lifting equipment comprises an area for handling, such as when fixing said lifting equipment to a wind tower component. Hereby it is ensured that a crane or similar lifting means can be used e.g. when placing the invented lifting equipment on its location of operation and thus ensuring that the operating people are not required to lift the equipment to the location manually. 
         [0024]    In another aspect of the invention said base frame comprises an area for connecting said lifting means e.g. a hole for attaching a crane wire and hook. Hereby it is ensured that a crane or similar lifting means can advantageously be used after placing the invented lifting equipment on its location of operation. 
         [0025]    The invention also provides a method for handling a wind turbine component, said method comprising steps of 
         [0026]    attaching lifting equipment according to one of the above-described embodiments to said wind turbine component, 
         [0027]    connecting lifting means to said lifting equipment, and 
         [0028]    handling the wind turbine component to a desired position. 
         [0029]    Hereby is an advantageous method to be used with the lifting equipment achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The invention will be described in the following with reference to the figures in which 
           [0031]      FIG. 1  illustrates a large modern wind turbine as seen from the front, 
           [0032]      FIG. 2   a  illustrates a conventional lifting equipment attached to a wind turbine tower segment, 
           [0033]      FIG. 2   b  illustrates an exploded view of a conventional lifting equipment attached to a wind turbine tower segment, 
           [0034]      FIG. 3  illustrates schematically a section of a wind turbine component, 
           [0035]      FIG. 4   a  illustrates a three-dimensional view of one embodiment of the universal lifting tool according to the invention, 
           [0036]      FIG. 4   b  illustrates a first side view of one embodiment of the universal lifting tool according to the invention, 
           [0037]      FIG. 4   c  illustrates a first cross sectional view of the universal lifting tool according to one embodiment of the invention, 
           [0038]      FIG. 4   d  illustrates a second side view of one embodiment of the universal lifting tool according to one embodiment of the invention, 
           [0039]      FIG. 5  illustrates a second cross sectional view of the universal lifting tool according to one embodiment of the invention, 
           [0040]      FIG. 6   a  illustrates schematically a three-dimensional view of a preferred embodiment of the invented universal lifting tool according to the present invention, 
           [0041]      FIG. 6   b  illustrates schematically a first side view of a preferred embodiment of the invention, 
           [0042]      FIG. 6   c  illustrates schematically a second view of a preferred embodiment of the invention, 
           [0043]      FIG. 7   a  illustrates schematically the invented universal lifting tool when attached to a wind turbine tower segment with a first radius, 
           [0044]      FIG. 7   b  illustrates schematically the universal lifting tool according to the invention when attached to a wind turbine tower segment with a second radius, 
           [0045]      FIG. 8  illustrates schematically an explored view of a preferred embodiment of the present invention attached to a wind turbine segment, and 
           [0046]      FIG. 9  illustrates schematically a view of a preferred embodiment of the present invention attached to and lifting a wind turbine tower segment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0047]      FIG. 1  illustrates a modern wind turbine  1 , comprising a tower  2  and a wind turbine nacelle  4  positioned on top of the tower  2 . The tower  2  is build up of a plurality of tower segments  3 . The wind turbine rotor  5 , comprising three wind turbine blades  6 , is connected to the nacelle  4  through the low speed shaft which extends out of the nacelle  4  front. 
         [0048]      FIG. 2   a  illustrates schematically one tower segment  3  with flanges  7 . Said flanges are constructed with a number of substantially equally spaced holes or connection points  8  around its centreline which is used for attaching the tower segments  3  when the tower  2  is erected. 
         [0049]    Besides for used in the purpose of attaching the tower segments to each other, the connection points  8  are often used as attachment points for lifting tool  9  during manufacturing, transportation and installation. As an example when erecting a wind turbine tower  2 , lifting tool  9  can be attached to e.g. 2, 4 or 8 locations distributed around the flange  7 . 
         [0050]    During installation and erection of a wind turbine tower  2  said plurality of different tower segments  3  must be placed on top of each other or on top of a foundation and be securely attached at said attachment points. 
         [0051]    The process of erecting a wind turbine tower comprises steps of
       attaching lifting tool  9 ,  12  to one or more locations around the flange  7 ,   attaching lifting means to said lifting tool  9 ,  12 ,   a first sequence of lifting the tower section  3  from the ground. In this sequence the forces acting between the tower section  3  and the lifting tool  9 ,  12  changes from being primarily shear forces (when the tower section  3  is in substantially horizontal position) to primarily tension forces (when the tower section  3  is free of the ground and is in substantially vertical position),   a second sequence of positioning the tower section  3  to its installation position on top of a foundation or an other tower section  3 , and   a third sequence of attaching and securing the tower section  3 .       
 
         [0057]      FIG. 2   b  illustrates an exploded view of one embodiment of the prior art of a conventional lifting tool  9  connected to said attachment points  8  during e.g. installation. The lifting tool comprises a base frame including an eyelet for the purpose of attaching e.g. a shackle  23  connected to lifting means (e.g. a crane) thru a wire  11 . 
         [0058]    During lifting the clamping bolts  10  are exposed to the gravitational forces of the tower via sheer and tension and must be dimensioned to comply with this. 
         [0059]      FIG. 3  illustrates an origin to a problem with prior art. Dependent on the construction of e.g. the flanges  7  of a wind turbine tower segment  3 , the distance % between the attachment points  8  and the angle α relative to horizontal may vary. This means that a lifting tool with fixed attachment points can only be attached to a component with attachment points distributed in a similar way. As e.g. the ends of wind turbine tower segments may have different radius and may have a variable number of attachment points, said l and α may vary in relation to the different tower segments. For the purpose of lifting, a different set of lifting equipment may therefore be required for each tower section. 
         [0060]      FIG. 4   a  illustrates a three-dimensional view of a universal lifting tool  12  according to one embodiment of the present invention. 
         [0061]    For this embodiment the universal lifting tool  12  comprises a base plate  13 , a lifting plate  14  and two side plates  15  which in total constitute a base frame for the invented universal lifting tool. 
         [0062]    The lifting plate  14  comprise an eyelet  21  for the attachment of tower lifting means e.g. via a shackle  23 . 
         [0063]    One of the side plates  15  comprise an eyelet  22  for the attachment of tool lifting means to be used when the invented universal lifting tool  12  is to be manoeuvred to its operating position. 
         [0064]    In one embodiment the invented universal lifting tool  12  is to be attached to three attachment points e.g.  8  of a flange  7  of a wind turbine tower section  3 . 
         [0065]    A middle attachment point comprises a strut  19  that penetrates the base plate  13  and is fastened to the base plate such as with two screws  20 . The strut can be replaced dependent on the diameter of the connection points  8  and can be e.g. 30 mm, 36 mm, 42 mm or 48 mm in diameter. 
         [0066]      FIG. 4   b  illustrates a first side view of the invented universal lifting tool according to one embodiment and illustrates the strut  19  penetrating the base plate  13 . 
         [0067]    One function of the strut  19  is to carry shear forces between the universal lifting tool  12  and the flanges  7  during said first sequence of lifting at said process of erecting a wind turbine tower  2 . 
         [0068]      FIG. 4   a  further illustrates that the two distal connection points of this embodiment  12  each comprises sleeves  16 ,  17  and a bush  18  located on top of each other. 
         [0069]    A first sleeve  16  is formed with a substantially circular hole  25  dislocated from the centre point of said first sleeve  16 . Said first sleeve  16  can rotate around its centre point as indicated by the dashed arrows. 
         [0070]    A second sleeve  17  is also formed with a circular hole  26  into which the bush  18  fits. The centre of said hole  26  is dislocated from the centre point of said second sleeve  17 . Said second sleeve can rotate around its centre point as indicated by the dashed arrows. 
         [0071]    The diameter of said hole  25  in said first sleeve  16  exceeds the diameter of said hole  26  in said second sleeve  17 . 
         [0072]    For the described embodiment of the invention, the base plate  13  is formed with a circular hole  24  for each distal attachment point (shown on  FIG. 5 ). The diameter of said hole  24  exceeds the diameter of said hole  25  of the second sleeve  16 . 
         [0073]    By placing the first  16  and second  17  sleeve on the base plate  13  as illustrated in  FIG. 4   a , and furthermore rotating them in relation to each other, it is possible to bring said hole  26  in the second sleeve  17  in position within the area of said hole  24  in the base plate  13  as desired with the positive result, that the distance l and the angle α relative to the fixed attachment point embodied by the strut  19 , can be changed to desired. 
         [0074]    It is hereby achieved that one lifting equipment  12  can be adapted to the connection points  8  of any tower section  3  despite of the angle α and distance l between the points  8 . 
         [0075]    This is further illustrated in  FIG. 4   c  where an exploded view of the attachment point  16   b - 18   b ,  13  of one embodiment of the lifting tool  12  is shown. It is illustrated that the holes  25 ,  26  in said first and second sleeve  16   b ,  17   b  respectively is dislocated from their centrelines c 1 , c 2  and that dependent on the rotation of the sleeves  16   b ,  17   b  in relation to the base frame  13 , the hole  26  in the second sleeve  17  can be brought in position within the area of said hole  24 . 
         [0076]      FIG. 4   d  illustrates a second side view of one embodiment of the invented lifting equipment. It is illustrated that the angle between the lifting plate  14  and the base plate  13  may be different from 90 degrees. 
         [0077]      FIG. 5  illustrates a cross sectional view of one embodiment of the invented lifting equipment comprising a base plate  13 , a first sleeve  16 , a second sleeve  17  and a bush  18 . 
         [0078]    In one embodiment the first sleeve  16  can be countersunk and fitted in the base plate  13 . For said embodiment a pointed screw  28  is used for the purpose of keeping said first sleeve  16  positioned during maneuvering of the lifting equipment. 
         [0079]    In another embodiment the second sleeve  17  can be countersunk and fitted in the first sleeve  16 . For said embodiment a pointed screw  28  is used for the purpose of keeping said second sleeve  17  positioned during maneuvering of the lifting equipment. 
         [0080]      FIGS. 6   a ,  6   b  and  6   c  illustrates different views of a preferred embodiment of the invented universal lifting tool. 
         [0081]    As illustrated in  FIG. 6   a  for this preferred embodiment, the universal lifting tool  12  comprises a base plate  13  that constitute a base frame and an eyelet  21  for the attachment of tower lifting means. 
         [0082]      FIG. 6   a  further illustrates that two connection points of this preferred embodiment  12  each comprises sleeves  16 ,  17  and a bush  18  located on top of each other. 
         [0083]    This example of a preferred embodiment is to be attached to three attachment points e.g.  8  of a flange  7  of a wind turbine tower section  3 . 
         [0084]    A middle attachment point (not illustrated in  FIG. 6   a ) comprises a strut  19  fastened to the base plate  13 . For various embodiments the strut can be replaced dependent on the diameter of the connection points  8  and can be e.g. 30 mm, 36 mm, 42 mm or 48 mm in diameter. 
         [0085]    Further a first sleeve  16  is formed with a substantially circular hole  25  (not illustrated at  FIG. 6   a .) dislocated from the centre point of said first sleeve  16 . Said first sleeve  16  can rotate around its centre point as indicated by the dashed arrows. 
         [0086]    A second sleeve  17  is also formed with a circular hole  26  (not illustrated on  FIG. 6   a ) into which the bush  18  fits. The centre of said hole  26  is dislocated from the centre point of said second sleeve  17 . Said second sleeve can rotate around its centre point as indicated by the dashed arrows. 
         [0087]    The diameter of said hole  25  in said first sleeve  16  exceeds the diameter of said hole  26  in said second sleeve  17 . 
         [0088]    By placing the first  16  and second  17  sleeve on the base plate  13  as illustrated in  FIG. 6   a , and furthermore rotating them in relation to each other, it is possible to bring said hole  26  in the second sleeve  17  in position within the area of said hole  24  in the base plate  13  as desired with the positive result, that the distance l and the angle α relative to the fixed attachment point embodied by the strut  19 , can be changed to desired. 
         [0089]    It is hereby achieved that one lifting equipment  12  can be adapted to the connection points  8  of any tower section  3  despite of the angle α and distance l between the points  8 . 
         [0090]    For one preferred embodiment the eyelet  21  is constructed in such a way that it penetrates the base plate  13  allowing tower lifting means comprising one or more lifting wires to be established through said eyelet  21 . This is further illustrated in  FIG. 8 . 
         [0091]    The entrance/exit traces of the eyelet  21  are curved and angled as to minimize stress on the wires and the base plate  13 . 
         [0092]    For various preferred embodiments, portions of the entrance/exit traces of the eyelet  21  are rotatable parts  27  and can follow any variation in angulation that occur e.g. when a connected horizontal positioned tower segment is raised to vertical position. 
         [0093]      FIG. 6   b  illustrates a first side view of a preferred embodiment of the invention comprising a strut  19 . 
         [0094]      FIG. 6   c  illustrates a second view of a preferred embodiment of the invention. 
         [0095]      FIGS. 7   a  and  7   b  illustrates schematically one embodiment of the invented universal lifting tool  12  attached to flanges  7  of wind turbine tower sections  3  with two different diameters. 
         [0096]      FIG. 7   a  illustrates a preferred positioning of the two sleeves  16  and  17  for a flange  7  with a first radius r 1 . 
         [0097]      FIG. 7   b  illustrates a preferred positioning of the two sleeves eccentrics  16  and  17  for a flange  7  with a second radius r 2  (i.e. r 1 &gt;r 2 ). 
         [0098]      FIG. 8  illustrates schematically a preferred embodiment of the invented universal lifting tool  12  attached to flanges  7  of a wind turbine tower section  3  and with attached lifting wire  11 . 
         [0099]      FIG. 9  illustrates schematically the invented universal lifting tools  12  attached to a wind turbine tower segment  3  when the segment is lifted to substantially vertical position.