Abstract:
A method for establishing access for mounting and dismounting of main shafts, gearbox, generator and other main parts located in the nacelle of a wind turbine, where the cabriolet remains localized on the nacelle, and guide transfer mechanisms are provided for mounting inside the nacelle. The basic idea is that the cabriolet is lifted upon rolls or roll sets which form the guide transfer mechanisms upward facing support surfaces, and that the cabriolet is stabilized by displaceable counter holds which are displaced and locked in position above the downwards positioned mounting flange, upon which the cabriolet can be displaced on the rollers or roll sets to a partly cantilevered position over the rear end of the nacelle. By the method, service on larger wind turbines can be performed without using mobile cranes, which saves resources.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a method for establishing access to the removal and installation of the main shaft, gearbox, generator and other main parts located in the nacelle of a wind turbine, the cabriolet remains localized on the nacelle, and guide mechanisms to perform the invention. 
         [0003]    2. Description of Related Art 
         [0004]    When carrying out service and repair work on large wind turbines, there is a need to be able to get access to mount and dismount vital and relatively heavy parts of the wind turbine, which is located in the interior of the nacelle. These parts are for example the main shaft, gearbox, generator and other major parts, which not can be transported up and down through the wind turbine tower, and where either the use of cranes or crane winch between the nacelle and a station on the ground, to handle said parts, which require that there is access to the nacelle from above. This access has so far been obtained by simply removing the nacelle cabriolet (the roof), and the hoist it down to earth by the use of a mobile crane and hoist the cabriolet in place after completion of servicing/repair of the windmill. This requires, however, the presence of a mobile crane, which is relatively expensive operation since the crane charged at the hourly rental. In cases where there used winches for the transport of the heavy parts from the nacelle and the ground surface, the handling of the nacelle cabriolet be a difficult operation due the relatively bulky design of the cabriolet, hence the need to operate with alternative solutions. 
         [0005]    An alternative option could be to mount the cabriolet on the nacelle with a hinge connection, and with hydraulically operated pistons, for example in combination with exchange mechanisms whereby the cabriolet could be opened as seen at smaller turbine types. However, such solutions require the installation of fixed installations in a nacelle, in which is already scarce space, and the solution is relatively expensive compared to the number of times where such installation is required. 
         [0006]    Thus, there is a need for an alternative solution to the above problem which is both flexible and which is universally applicable for convertibles on the nacelles of different sizes and types of wind turbines. 
       SUMMARY OF THE INVENTION 
       [0007]    It is the object of the invention to provide a solution where the cabriolet remains on the nacelle top, but at the same time establishes access for removal and installation, as well as hoisting up and down of a wind turbine main shaft, gearbox, generator and other major parts are arranged in the nacelle on wind turbines. 
         [0008]    This object is achieved by a method for establishing access to the removal and installation of the main shaft, gearbox, generator and other main parts located in the nacelle of a wind turbine, where the nacelle cabriolet remains on the nacelle and comprising the following operations;
       mounting at least two sets of pairs of opposing guide transfer mechanisms on the inner side of the nacelle respectively near the front end (the shaft end) and the rear end, the upwardly facing free ends of which comprises at least one roller,   displacement of the free ends of the guiding transfer means to abutment with the abutment flange of the cabriolet relative to the nacelle base by jacks or winches,   displacement of a counter holding roller located in the level above the roller(s) and the abutment flange of the cabriolet in position above the abutment flange of the cabriolet at each guide transfer mechanism, and   displacement of the cabriolet in a backwards direction, away from the front end, to a position where a part of the cabriolet is cantilevered over the rear edge of the nacelle.       
 
         [0013]    This provides the possibility to perform a rearward displacement of the nacelle cabriolet to an extent, which results in providing sufficient access to remove major parts of the interior of the nacelle by means of winches, without the use of an actual crane. 
         [0014]    A guide transfer mechanism, for mounting on the inner surface of a nacelle with a cabriolet and/or mounting to the static stable parts of a wind turbine arranged in the nacelle, for lifting and displacement of the cabriolet on the nacelle of wind is characterized in, that the guide transfer mechanism comprises a console with mounting facilities for mounting the console in the inside of the nacelle and/or static stable parts of the wind turbine arranged in the nacelle, said console comprising a first horizontally orientated frame section, and a from this second integrated vertically orientated, downwards extending, tube shaped part, for receiving and guiding of a therein vertical displaceable cooperating first member, the first lower end of which is adapted to cooperate with lifting means for displacement of the first member, and the other upper end of which comprises at least a first roller, or roller set, the upwards facing carrying surface is located in the same horizontal plane and mounted on horizontally oriented shaft(s). 
         [0015]    Hereby is achieved the advantage that the guide transfer mechanisms used for lifting and displacement of the cabriolet, can be mounted on any wind turbine and removed again after use, that is, to the universal application principle is ensured. The advantage is also that by displacement of the vertically oriented displaceable first means in the upward direction by means of a jack, winch, a pulley block or other suitable means it is obtained that the roll or roll set in the upper free end of the displaceable member is brought into abutment with the downwardly facing side of the flange of the cabriolet, and a continued upward displacement of the member will result in that the cabriolet come to rest on the roll or roll set, or, more correct expressed, the rollers of each of the four supporting points, whereby the cabriolet can be displaced some backward, in the direction away from the hub of the wind turbine, in a carefully controlled movement, possibly guided by pulleys, winches, lashing straps, or similar equipment, thus ensuring that the cabriolet do not run off the rolls, and dropped. 
         [0016]    The guide transfer mechanisms can be transported from the surface to the nacelle inside the wind turbine tower may be designed in light metal or composite material in order to reduce weight accordingly, which will facilitate its handling and fitting. 
         [0017]    With the intent of ensuring that the displacement of the cabriolet should not be exaggerated so that it is dropped, the guide transfer mechanism further comprises a second roll, or counter hold, mounted on a horizontally oriented shaft, located at a level above the first roll or roll set, said second roller or counter hold is displaceable between a passive retracted position, where the roller or counter hold is located outside the first rolling bearing surface, and an advanced, active lockable position where the second roller or the counter hold is positioned at a level above the first roll or roll set&#39;s bearing surface. 
         [0018]    By placing the counter hold or roll in the active projecting locked position, it is achieved that the displacement of the cabriolet is limited by the second roller or counter hold, so that the displacement is limited to the point where the roller or the counter hold comes in abutment with the inner surface of the front end of cabriolet, and simultaneously controlled displacement of the cabriolet parallel to the nacelle. Moreover, the counter hold ensures that the cabriolet does not tilt over its center of gravity, and thus, is the lost. The counter hold or roller also ensures the cabriolet against gust of wind. 
         [0019]    With the intent to maximize stability during displacement of cabriolet, the guide transfer mechanism according to the invention may comprise locking means between the vertically oriented tubular member and the vertically displaceable member for attachment of the vertically displaceable first member in a preferred position. 
         [0020]    Hereby is achieved that the vertically displaceable member is lockable with the roll or roll set at a preferred level, and thus there is provided a stable support of the rollers or roller sets on which the cabriolet can be displaced. The locking means may for example consist in through-holes in the vertical tubular member and the sliding body which can be made to overlap by adjusting the displacement of the body with jacks, winches, pulley blocks, etc. after which a locking bolt is introduced through the overlapping holes and secured with a locking ring, split or similar. Then, slacken the means used for the displacement of the body, then roll/roll set is supported by the locking bolt. 
         [0021]    With the intention further to stabilize the rear guide transfer mechanisms, the first horizontally oriented frame section may further comprise cooperating mounting facilities at the first end of the horizontally oriented, and with respect to the first frame part longitudinal axis, obliquely extending support beams, the other end of which includes mounting facilities for mounting for fitting on an inner adjacent side of the nacelle. 
         [0022]    This provides better stability of the rear transfer mechanisms against twisting, provided that the cabriolet during the displacement is influenced by wind or other forces which do not run parallel to the longitudinal axis of the nacelle. 
         [0023]    In a particular embodiment of the guide transfer mechanism according to the invention, the vertically displaceable cooperating first member comprises a jack, for displacement of the first member in the vertical direction, guided in the vertically oriented tubular member. 
         [0024]    The embodiment will inevitably cause the guide transfer mechanism becomes heavier to handle, but can in some cases be advantageous. 
         [0025]    In a further embodiment of the guide transfer mechanism according to the invention, the first lower end of the vertically displaceable cooperating first member comprise a groove cut wheel which cooperates with a winch, a pulley block or lashing straps belonging to the guide transfer mechanism, the ends of which are attachable to the bracket, and passed through the groove cut wheels for the displacement of the first member in the vertical direction guided in the vertical tubular member. 
         [0026]    The invention is briefly described in the following with reference to the accompanied drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1  is a view of a nacelle on a wind turbine seen from above, where the cabriolet is closed, 
           [0028]      FIG. 2  is a view of the nacelle in  FIG. 1  seen from above, but with the cabriolet displaced backwards according to the method according to the invention, 
           [0029]      FIG. 3  is a perspective view of  FIG. 2 , 
           [0030]      FIG. 4  is a perspective detail section view of the nacelle shown in  FIGS. 2 and 3  seen obliquely from behind, and where the cabriolet is transparent, 
           [0031]      FIG. 5  shows a first embodiment of a guide transfer mechanism for mounting on statically stable structural components mounted near the front end of the nacelle, to perform the method according to the invention, 
           [0032]      FIG. 6  is a detail perspective view of the embodiment of a guide transfer mechanism shown in  FIG. 5 , 
           [0033]      FIG. 7  shows a second embodiment of a guide transfer mechanism for mounting on the nacelle sides, mounted near the rear end of the nacelle, 
           [0034]      FIG. 8  is a first detail perspective view of the embodiment of a guide transfer mechanism shown in  FIG. 7 , 
           [0035]      FIG. 9  is a second detail perspective view of the embodiment of a guide transfer mechanism shown in  FIGS. 7 and 8 , and 
           [0036]      FIG. 10  is a detail perspective view of the second upper end of the guide transfer mechanism according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]      FIG. 1  is a view of the nacelle  2  on a wind turbine  4  seen from above where the cabriolet  6  is closed. The nacelle has a front end  8  and a rear end  10 , and a center axis  12 . In the view the cabriolet is made transparent. 
         [0038]    In  FIG. 2 , which is a view of the nacelle  2  shown in  FIG. 1 , the cabriolet is displaced backwards above the rear end  10  of the nacelle so the main shaft  14  and the gearbox  16  etc. of the wind turbine is exposed. 
         [0039]    In  FIG. 3 , which is a perspective view of the nacelle shown in  FIGS. 1 and 2 , where the nacelle  2  and the cabriolet  6  is made transparent, appears how the cabriolet  6  is raised and carried respectively on a first set of guide transfer mechanisms  18 ,  18 ′, mounted on statically stable structural components  20  in the nacelle  2  close to the front end  8  of the nacelle, and a second set of guide transfer mechanisms  22 ,  22 ′ mounted on the parallel long sides  24 ,  24 ′ of the nacelle and with support beams  26  mounted on the rear side  28  of the nacelle. 
         [0040]    In  FIG. 4 , which is a perspective section view of the nacelle  2  seen obliquely from behind and above, it appears more in detail how the first set of guide transfer mechanisms  18 ,  18 ′ is mounted to mechanical stable structural components  20  close to the front end  8  of the nacelle, and how the second set of guide transfer mechanisms  22 ,  22 ′ is mounted on the parallel sides  24 ,  24 ′ of the nacelle  2 . 
         [0041]    In  FIG. 5  is disclosed a detail section showing how the first guide transfer mechanism  18  is mounted to a mechanical stable structural component  20  in the nacelle  2 . The mounting facilities  28  consists in the shown embodiment of a stiffened angle frame  30 , the vertical oriented leg  32  of which is connected with a first horizontally oriented frame part  34  near the nacelle wall  24 , and the horizontally oriented angle leg  36  via spacers  38  and bolts  40  introduced through mating holes  41  in the angle leg  36 , is fixed to the mechanically stable structural member  20 . 
         [0042]    As it further appears from  FIG. 5 , and more clearly from  FIG. 6 , which is a perspective view of an embodiment of the first guide transfer mechanism  18 ,  18 ′ where its design is seen more in detail. The guide transfer mechanism  18 ,  18 ′ comprises the first horizontally oriented frame section  34  which is attached to the angle frame  30 . 
         [0043]    In  FIG. 7 , is shown a second embodiment  22 ,  22 ′ of the guide transfer mechanism suited for mounting on respectively the inner long sides  24 ,  24 ′ of the nacelle  2  and on the inner rear wall  28  of the nacelle. This embodiment of the guide transfer mechanism comprises besides the first horizontally oriented frame section  34  with mounting facilities  66  for mounting on the nacelle sides  24 ,  24 ′, further an oblique extending frame part  68 , the free end of which  70  includes mounting facilities  71  on the rear wall  28  of the nacelle  2 . This will provide this second embodiment  22 ,  22 ′ of the guide transfer mechanism the required stability to withstand the forces to be transferred to the nacelle sides when the cabriolet  2  is displaced backwards and forwards. 
         [0044]    Common to the illustrated embodiments of the guide transfer mechanisms  18 ,  18 ′ and  22 ,  22 ′ is that a second integrated vertically oriented tube shaped part  42  extends downwards from the first integrated frame part  34 , the second integrated vertically orientated tube shaped part  42  being designed for receiving and guiding a vertically displaceable first member  44 , the first lower end  46  in the illustrated embodiment is provided with a groove cut wheel  48  arranged to cooperate with lifting means (not shown) for displacement of the first member  44 , guided inside the vertically oriented tube shaped part  42 . The lifting means for use with the illustrated embodiment may be formed of a pulley block and a lashing with a tighten mechanism, the ends of which is attached to cross pins  50  arranged on each side of the tube shaped part  42  on the frame  34 . By guiding the wire of the winch, the chain of the pulley block, or the lashing strap down and around the groove cut wheel  48 , and subsequently tighten the wire, chain or the lashing strap with the suitable tighten mechanisms, there is performed a displacement of the first member  44  in vertical direction. 
         [0045]    The second upper end  52  of the vertical displaceable member  44  comprises in the embodiment shown, a set of rolls comprising three rolls  54 , whose upwardly facing support surface  55  is located in the same horizontal plane and mounted on horizontally oriented shafts  56  It is the roller upwardly facing supporting surfaces  55 , which at an upwardly-oriented displacement of the vertically displaceable member  44 , is brought into abutment with the flange  58  on the lower side  60  of the cabriolet  6  (see also FIG.  10 ,) and by continued displacement of the member  44  upwards by the lifting means, the cabriolet  6  is lifted free of nacelle edge and can subsequently be displaced carried on rollers  54 . 
         [0046]    As is apparent from  FIGS. 5-10 , the guide transfer mechanism further comprises another roll or a counter hold  62 , mounted on a horizontally oriented shaft  64  located in a level of the first roll set  54 , the second roller or counter hold  62  is displaceable between a passive retracted position, in which the reel/counter hold  62  is located outside the support surface  55  of the first roll, and a forward, active position in which the second roller/counter hold  62  is positioned at a level above the supporting surface  55  of the first roller set  54 . 
         [0047]    Common to the embodiments of the guide transfer mechanism  18   18 ′ and  22 ,  22 ′ also applies to include locking means  70  between the vertically oriented tubular member  42  and the vertically displaceable first member  44  for retaining of the vertically displaceable first member  44  in a preferred position. The locking means  70  in the illustrated embodiments comprises the vertical tubular portion  42  and the displaceable member  44  comprises through-holes  72 ,  74  which can be made to overlap by adjusting the displacement of the body  44  with jacks, winches and pulley blocks etc. (not shown) after which a locking bolt  76  which is secured with a locking ring, split or similar (not shown) is introduced through the overlapping holes  72 ,  74 . Then, the lifting means used for the displacement of the body is slackened, after which roll set  54  is supported by the bolt  76 . 
         [0048]    Access to mounting and de-mounting main shafts  14 , gearbox  16 , generator and other main parts arranged in the nacelle  2  on a wind turbine, without removing the cabriolet  2  from the nacelle  2  comprises the following operations;
       mounting at least two sets of pairs of opposing guide transfer mechanisms  18 ,  18 ′,  22 ,  22 ′, the upwardly facing free ends  52  of which comprises at least one roller  54 , on the inner side of the nacelle close to respectively near the front end (the shaft end) and the rear end.   displacement of the free ends  52  of the guide transfer mechanisms  18 ,  18 ′, 22 ,  22 ′ to abutment with the abutment flange  58  of the cabriolet by jacks or winches,   displacement of a counter holding roller  62  located in the level above the roller(s)  54  and the abutment flange  58  of the cabriolet in position above the abutment flange  58  of the cabriolet at each guide transfer mechanism  18 ,  18 ′,  22 ,  22 ′, and   displacement of the cabriolet  2  in backwards direction, away from the front end  8  of the nacelle  2  to a position where a part of the cabriolet  2  is cantilevered over the rear edge  10  of the nacelle.       
 
         [0053]    Upon completion of work in the nacelle, the cabriolet  2  is displaced on the rollers  54 , back to the original position, where after the vertically displaceable member  44  on the guide transfer mechanisms  18 ,  18 ′,  22 ,  22 ′ are lowered to the starting position and subsequently, the cabriolet is attached to the nacelle, and finally the guide transfer mechanisms  18 ,  18 ′,  22 ,  22 ′ are removed. 
         [0054]    Finally, it is noted that the inventor has recognized that the guide transfer mechanism may be embodied in other designs than those described above and shown in the accompanying drawings. For example, each guide transfer mechanism  18 ,  18 ′,  22 ,  22 ′ could be equipped with an integrated jack, and the number of rolls  54  and counter holds  62  may be more or less than the number disclosed, but this does not alter the essential inventive aspect to provide access to the removal and installation of the main shaft, gearbox, generator and other main parts located in the nacelle of a wind turbine, without removal of the nacelle cabriolet from the nacelle, by providing the nacelle  2  with a number of guide transfer mechanisms  18 ,  18 ′,  22 ,  22 ′ with supporting rollers  54 , on which the cabriolet  2  can be displaced sufficiently backward to be establish the appropriate access, as well as with lockable counter hold  62  for retaining and control of the displacement of the cabriolet.