Abstract:
A fixing system for cables, in particular in wind turbines, includes a main body ( 1 ) that can be fixed to a supporting structure and cable holders ( 11 ) that have an opening for cables to be inserted. Each opening can be closed by a cover device ( 45 ). The cable holders ( 11 ) are mounted on the main body ( 1 ) and in an arrangement extending at least over a part of a circle with the opening of the cable holders on the outside. The cover device includes retaining elements ( 45 ), by which the opening of the respective cable holders ( 11 ) can be blocked to secure inserted cables.

Description:
FIELD OF THE INVENTION 
     The invention relates to a fixing system for cables, in particular in wind turbines, having a main body that can be fixed to a supporting structure and that has cable holders. The cable holders have openings for the insertion of cables, with each opening able to be sealed by a cover device. 
     BACKGROUND OF THE INVENTION 
     To discharge the energy generated in wind turbines, as well as for other operational purposes such as control, monitoring and the like, cables extending though the tower into the nacelle must be reliably fastened to the appropriate supporting structures, in particular to the tower segments. Fastenings with clamp-like main bodies in which inserted cables can be secured are typically used for this purpose. Fixing systems of this kind in which a corresponding number of screwing procedures must also be carried out, require a high degree of assembly expenditure. This expenditure applies in particular to the fastening of cables that must be routed from below, through the tower to the nacelle and connected to the generator unit. In the case of conventional wind turbines, this generator unit may need to be rotated together with the nacelle for up to three turns before the nacelle is steered back. For the cables to be able to make this movement as well, they are routed over a cable loop hanging in the tower. To prevent the cables from rubbing against one another during the rotational movements, the cables must be kept at a distance here. Cables are therefore typically held by a round supporting structure, for example in the form of a tubular piece, around which the cables are distributed and fastened using simple clamps. Mountings of this kind are costly and tedious. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide an improved and especially suitable fixing system for cables. 
     This objective is basically achieved according to the invention by a fixing system comprising cable holders provided in the form of components that can be mounted on a main body and are disposed on the main body in an arrangement extending at least over a part of a ring with the openings of the cable holders on the outside. A cover device has retaining elements. The openings of the cable holders can be blocked by the retaining elements to fasten, in particular to pre-fasten, the inserted cables. 
     The annular arrangement of the cable holders allows the cables to be fixed in a cable loop hanging from the nacelle in the tower such that those cables are positioned and distanced from one another as in the tower segments themselves. Chafing of the cables can then be avoided in any event. The fact that further cable holders are provided in the form of components that can be mounted on the main body provides the advantageous possibility of realizing a fixing system that can tolerate especially high loads with little design effort and at a low cost. In the case of separate cable holders that can be attached to the main body, different materials can be used for these cable holders and the main body. Thus cable holders can be efficiently and cost-effectively molded out of a plastic material, for example, while the main body can be formed as a metal structure, for instance in the form of a steel structure with a high degree of structural stability, i.e. it can be designed for optimal stability without having to forgo the use of cable holders made out of inexpensive materials. According to the invention, retaining devices are also available as an element of the cover device. By the retaining devices, the insertion opening can be blocked to pre-fasten the cables inserted into the cable guides of the cable holders, allowing the cables to be readily inserted into the cable guides, one after the other, since they are secured against falling out. 
     Since the cover device preferably also has a band clamp, which band clamp exerts the retaining force on the cables via the retaining devices, only a single screwing procedure is needed to tension the band clamp to secure the total number of cables held in the annular arrangement. A retaining force can also be exerted on the received cables by the cover device, if necessary. 
     In especially advantageous embodiments, the main body comprises a steel band positioned between end sections that form attachment points for anchoring on the supporting structure. The steel band extends preferably as a part of an arc that forms a circular ring, along which a row of cable holders is mounted. This kind of steel supporting structure ensures that the cables are securely anchored, even if the cable holders are made of a lower strength material such as plastic. 
     An overall structure with an especially high degree of stability can be achieved with a cross-member in the form of an axis extending through the inside of the arc. The cross-member penetrates the band of the are on both sides between the end sections that serve as anchoring sites and the respective end of the row of cable holders and projects outward. The projecting ends of the cross-member each form a point of application for the band clamp. Such cross-member, in particular if it is welded to the band at the penetration points through the band, forms a particularly effective reinforcement of the arc that runs semicircularly, for example, so that a high degree of stability is assured with a low material cost. At the same time, due to the cross-member, points of application for the band clamp are available, to which the clamping force can be introduced into the structure with force components that predominantly run longitudinally with respect to the band and therefore with greater operational reliability. 
     In especially preferred embodiments, the cross-member is formed by a steel rod, with a rectangular cross section and a long side extending in the circumferential direction of the arc and passing through a slot in the bracket band arc. In this arrangement, the clamping force of the band clamp is exerted in the direction of the long sides of the rectangular profile, thus in the direction of the greater bending resistance of the cross-member. 
     Each cable holder is preferably individually connected to the band of the main body, and each has a trough-shaped cable guide. 
     Particularly advantageously, the cable holders can have a curved base corresponding to the curvature of the band for installation on the band. A catch mechanism is formed between this curved base and the band to secure the cable holders on the main body. Such system is characterized by an especially low degree of installation effort. 
     The exact orientation of the cable holders on the band is very easy to achieve when the cable holders are disposed between positioning fittings. The position fittings extend radially in a row in the circumferential direction of the band from the circular arcuate band and engage with guide channels formed by recesses in the side walls of the cable holders in a fitted manner. The positioning fittings also serve to accept forces exerted between the cable holders and main body. 
     In especially preferred embodiments, the retaining devices are pivotably mounted on the edge of the opening of the trough-shaped cable guides of the cable holders such that the retaining devices can be moved between an insertion position that can be turned away from the opening and a pre-fastening position securing the inserted cables. A locking device secures the cable holders in the pre-fastening position and is provided between the cable holders and retaining devices. The retaining devices are secured to the respective cable holder by the pivotal mounting of the retaining devices on the cable holder so that they are non-detachable and need not be handled separately for each assembly process. 
     In especially advantageous embodiments, the retaining devices have a cover member that is hinged on the cable holder and forms a support surface on its upper side for the band clamp. A displaceable clamping member on the cover member is advanced by a spring arrangement in the direction of the received cable. If necessary, a pre-clamping force can also be realized in such a way. 
     Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings that form a part of this disclosure: 
         FIG. 1  is a perspective of a main body only of a fixing system according to a first exemplary embodiment of the invention, without cable holders attached to the main body; 
         FIG. 2  is an enlarged and partial perspective view of the fixing system of  FIG. 1  showing only one last cable holder and part of one preceding cable holder from a row of cable holders attached to the main body; 
         FIG. 3  is an enlarged and partial front elevational view of the fixing system of  FIG. 1  showing two successive cable holders; 
         FIG. 4  is an enlarged and partial front elevational view in section of the fixing system of  FIG. 1 ; 
         FIG. 5  is an enlarged perspective view of an individual cable holder of the fixing system of  FIG. 1 ; 
         FIG. 6  is an enlarged perspective view in section of an individual retaining device of the fixing system of  FIG. 1 ; and 
         FIG. 7  is a perspective view of a main body only of a fixing system according to a second exemplary embodiment of the invention, without cable holders attached to the main body. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  separately shows the main body  1  of an embodiment to be described, without attached cable holders. The main body  1  is a steel structure comprising a steel band  3  that is bent into a semicircle between the end sections  5 . At the end sections  5 , angled brackets  7  with elongated holes  9  serve to anchor the main body  1  to a supporting structure. The brackets  7  are angled in relation to the end sections  5  to match the curvature of the tower wall to allow the brackets to be attached to the inner surface of a tower wall in wind turbines. In the present example, the arc of the band  3  extending between the end sections  5  forms the mount for eight cable holders that are not shown in the depiction of the main body  1  in  FIG. 1 . The cable holders  11  are shown in  FIGS. 2-5 . To attach the cable holders  1  to the band  3  of the main body  1 , the band  3  has fastening holes  13  so that each cable holder  11  can be attached equally spaced along the circular arc. Each fastening hole  13  serving as a catch mechanism with the cable holder  11 , in which a snap-in connection with a snap-in ridge  15  ( FIGS. 4 and 5 ) is formed, which snap-in ridge  15  projects from the base  17  ( FIG. 5 ) of the respective cable holder  11 . As can be most clearly seen in  FIG. 5 , the base  17  has a curvature adapted to the circular arc of the band  3 .  FIG. 4  shows the formed snap-in connection. 
     As shown in  FIGS. 2 and 3 , when the cable holders  11  are attached to the band  3 , they lie with their side surfaces  19  ( FIG. 5 ) flush with one another so that the cable holders  11  on the main body  1  form an uninterrupted arcuate row. As shown in  FIG. 5 , continuous recesses  21  are located in the side surfaces  19  of the cable holders  11  from the base  17  to the upper end. The recesses are formed such that when the side surfaces  19  of two consecutive cable holders  11  lie flush against one another, positioning fittings can be appropriately accommodated in the recesses  21 . Here, this accommodation involves cylindrical studs  23  that sit, are pressed, welded or glued in the stud holes  25  ( FIG. 4 ) of the band  3 , and that extend radially from the arc of the band  3 . The recesses  21  in the cable holders  11  have an inner partial cylindrical surface  25  fitted to the studs  23 . The positioning fittings may also have another cross-sectional shape. 
     As shown in  FIG. 1 , a cross-member  31  extends through the arc of the band  3  in the manner of a bowstring. The cross-member is formed by a steel rod having a rectangular cross section and passes through slots  33  in the band  3 . The end sections  35  of the cross-member extend outward in a radial direction relative to the circular arc of the band  3 . An anchoring point  37  for a respective end of the band clamp  39  is formed at the end sections  35  of the cross-member  31 . The band clamp  39  encircles the row of cable holders  11  (see  FIGS. 2 and 3 ). The cross-member  31  is guided in an orientation through the slots  33  of the band  3  such that the long sides of the rectangular profile face the circumferential direction of the band  3 , and the cross-member  31  thereby counteracts the higher bending resistance of the tensile force of the band clamp  39  exerted in the circumferential direction. In the row of cable holders  11  disposed along the arc of the band  3 , the two end sections  35  of the cross-member  31  each replace the outer positioning studs  23  of the respective final cable holder  11 . Adapted to the rectangular shape of these end sections  35 , a further recessed groove  41  ( FIG. 5 ), connecting to the partial cylindrical surface  25 , is located in the respective recess  21  of the side surface  19  of the cable holders  11  at the bottom of the recess  21 . The end section  35  of the cross-member  31  suitably engages recessed groove  4 . 
     As shown in  FIGS. 1 ,  2  and  3 , the band clamp  39  can be tensioned by a turnbuckle  43  ( FIG. 3 ) corresponding to the prior art, and is in contact with the upper side of the retaining devices  45 . The cable holders  11  each have a trough-shaped cable guide  47  that tapers towards the bottom of the trough. The upper end of cable guide  47  has an insertion opening for inserting the cable (not shown). The retaining devices  45  have a lower clamping member  51  below an upper cover member. The upper cover member forms the contact surface for the band clamp  39  on its upper side. In the operating state shown in  FIGS. 2 and 3 , this lower clamping member  51  extends over the insertion opening of the respective cable guide  47 , exerting force on the inserted cables. 
     The retaining devices  45  have hinge plates  53  on one side of the cover member  49  thereof. With those hinge plates  53 , the retaining devices can be pivoted, as on a hinge, on a swivel bearing  55  located on the cable holders  11  at the insertion opening thereof. Compared to the position shown in  FIGS. 2 and 3 , the retaining devices  45  can therefore be pivoted up into an insertion position, so that the cables can be inserted into the cable guides  47  before the band clamp  39  is applied, closed, and tensioned. Once the insertion process has been carried out at the respective cable holder  11 , the retaining devices  45  are pivoted from the insertion position into a pre-fastening position on the cable holder  47 . In this pre-fastening position, the retaining devices  45  can each be secured by flexible snap-in tongues  57  formed on the cover member  49  on the side opposite the hinge plates  53 . These snap-in tongues  57  engage with snap-in tabs  59  on the cable holders  11 . After the retaining devices  45  are thus pre-fixed, the band clamp  39  is guided over the cover members  49  of the retaining devices  45  and tensioned by the turnbuckle  53 . If the retaining devices  45  can be held in a position, defined by a snap-in or other immobilizing connection, that closes or blocks the cable holders  11 . In one embodiment, not depicted here, the band clamp can be omitted entirely. 
       FIG. 6  illustrates an embodiment of the retaining devices  45 . Instead of forming these retaining devices as a one-piece component, for example as a molded part made of plastic, the retaining devices  45  can have a clamping member  51  that is relatively movable with respect to the cover member  49 , as shown in  FIG. 6 . In this case, the clamping member  51  has the form of a rectangular plate, from the corner regions of which guide bars  63  extend in the direction of the cover member  49  and are guided so that they can be displaced in guide surfaces  65  in the cover member  49 . A compound spring comprising multiple compression springs  67  is inserted between clamping member  51  and the cover member  49 . The compression springs bias the clamping member  51  to advance in the direction of the cable to their positioning. To limit the spring deflection and to prevent the escape of the clamping member  51  from the formed spring case under the load of the compound spring, end stop projections  69  and  71  are provided on the guide  65  on the cover member  49  and on the guide bars  63  of the clamping member  51 , respectively. 
     Due to the rigid steel structure forming the main body  1 , the cable holders  11 , the retaining devices  45 , as well as the positioning studs  23 , can be made out of a low cost material that allows efficient production, for example out of molded plastic. 
       FIG. 7  shows a separate depiction of the main body of a modified embodiment. In contrast to the above-described example, an alignment device is provided on the main body  1 . This alignment device is provided in particular for applications in which the main body  1  is to be mounted on the inner wall of a conically formed tower segment in a wind turbine. The tower segment tapers in diameter to the nacelle so that the inner wall has a sloping gradient relative to the vertical. The orientation of the plane of the arc  3  can be aligned with the cable holders  11  in an orientation that is adapted to the respective wall inclination by this alignment device. 
     To this end, the alignment device has cantilevers  71  extending from the end sections  5  of the band  3  in the same respective direction. At the end of each cantilever  71 , a threaded sleeve  73  is located. An adjustment screw  75  located in each threaded sleeve  73 . The free end  77  of each screw is supported on the inner wall of the tower segment in question and allows the desired position of the level of the arc  3  to be adjusted relative to the tower wall. 
     While various embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.