Abstract:
An attachment system for cables ( 7 ), in particular for wind turbines, has a base body ( 1, 3 ) securable to a support structure and forming cable bushings ( 5 ) with openings for cables ( 7 ). The openings can be closed by a cover ( 17 ) applying retaining forces to the cables ( 7 ). The cable bushings ( 5 ) on the base body ( 1, 3 ) are arranged at least over part of a ring, with an outside opening. The cover ( 17 ) has retaining bodies lockable to the base body ( 1, 3 ) for preliminary fixing of the cables ( 7 ) inserted into the cable bushings ( 5 ) and a tightening strap ( 17 ) encompassing the base body ( 1, 3 ) and applying retaining forces to the cables ( 7 ) via the retaining bodies.

Description:
FIELD OF THE INVENTION 
     The invention relates to an attachment system for cables, in particular for wind turbines, having a base body securable to a support structure and forming cable bushings. Each cable bushing has an opening for the insertion of cables that can be closed by a cover applying a retaining force to the cables. 
     BACKGROUND OF THE INVENTION 
     To deliver the energy produced in wind turbines and for other operating purposes, such as control, monitoring and the like, cables leading through the tower into the nacelle can be reliably secured to the corresponding support structures, especially the tower segments. Usually, attachments with clamp-like base bodies are used for this purpose, in which the cables inserted into them can be secured. These attachment systems in which a corresponding number of screwing processes must be carried out require high mounting effort. This requirement applies especially to the attachment of cables routed from below through the tower to the nacelle and connected to the generator unit. In conventional wind turbines, this generator unit together with the nacelle can execute up to three revolutions before the nacelle is set back. So that the cables can also execute the motion, they are routed over a cable loop hanging into the tower. To prevent the cables from chafing one another during rotary motion, the cables must be kept at a distance from each other. For this purpose, the cables are conventionally held by a round support structure, for example, in the form of a pipe section around which the cables are distributed and attached thereto with simple clamps. This type of installation takes place at a considerable height and is very complex. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide an improved attachment system especially suited to use with cables for wind turbines. 
     According to the invention, this object is basically achieved by an attachment system forming a cable loop hanging from the nacelle into the tower by cable bushings on a base body located in an arrangement extending over at least one part of a ring, with openings situated on its outside. Retaining bodies as a component of the cover can be locked to the base body for preliminary fixing of the cables inserted into the cable bushings. The cables can be easily inserted in succession into the cable bushings since they are protected against falling out. Since the cover has a tightening strap applying the retaining force to the cables via the retaining bodies, only a single screw connection process for tensioning the tightening strap is necessary to secure all the cables held in the ring arrangement. 
     As one preferred embodiment, the base body can have the shape of a circular ring body with an inner ring attached to a preferably round support part and an outer ring surrounding the inner ring at a distance and forming the cable bushings. The cables fixed thereto thus form a cable ring with a corresponding radial distance to the support part so that a cable group of relatively large diameter with a correspondingly large number of individual cables can be formed. 
     For attachment of the base body to a flat support structure, the base body can have a ring part forming the cable bushings and extending over part of a circular line. The partial circular line ends are connected by a crosspiece integral with it in the form of a straight beam connected to the support part in the form of a bracket whose ends project over the respective ends of the beam. The ends of the tightening strap are anchored to the projecting ends. 
     While the ring body or the ring part preferably form a full circle or a partial circle, a non-round, for example, polygonal, ring shape is possible. 
     In especially advantageous exemplary embodiments, the base body can have cable bushings in the form of tub-like trough-shaped bodies connected to one another by wall parts extending in the peripheral direction. In such configuration, the retaining bodies can have a clamping part projecting into the opening of the trough-shaped bodies in the operating position and forming a contact surface applying the retaining force to the respective cables. 
     The arrangement can be especially advantageously made such that the cover surface of the retaining bodies opposite the contact surface as the bearing surface of the tightening strap has an arch matched to the peripheral circular line of the outer ring. The cover surface of the retaining bodies shaped in this way forms not only protection against the tightening strap, but also forms a part of an imaginary peripheral cylindrical surface of the outer ring for optimum flat contact of the tightening strap. 
     With respect to the configuration of the outer ring, advantageously the outer ring between the trough-shaped bodies has two wall parts, each of which delimits the axial outer sides of the outer ring and in which on both sides of the trough-shaped bodies, recesses are radially open to the outside. Catches are made in the wall parts so that the retaining bodies can be protected against motion directed radially to the outside with catch projections provided on the parts of the retaining bodies overlapping the trough-shaped bodies. Advantageously, in this exemplary embodiment, the wall parts on both sides of the contact surface located on the cover surface of the retaining bodies can form guide surfaces for lateral guidance of the tightening strap. 
     In other advantageous exemplary embodiments, the trough-shaped bodies on their outer sides can be overlapped by parts of the retaining bodies and have projections made such that the retaining bodies with the catch projections located thereon can be secured against motion directed radially to the outside. 
     In such exemplary embodiments, the cover surface of the retaining parts can have radially protruding guide projections forming guide surfaces for lateral guidance of the tightening strap. 
     The retaining bodies can be made as one-piece injection moldings, but can alternatively be formed from two identically made parts connected to one another. Each part has protruding guide projections as guide surfaces for each side of the tightening. 
     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 which form a part of this disclosure: 
         FIG. 1  is a perspective view of an attachment system according to a first exemplary embodiment of the invention, the attachment of only three cables being indicated by way of example; 
         FIG. 2  is an enlarged partial perspective view of only one peripheral segment of the attachment system of  FIG. 1 ; 
         FIG. 3  is an enlarged, partial perspective view according to a second exemplary embodiment of the invention; 
         FIG. 4  is an enlarged perspective view of only one retaining body as a component of the attachment system according to first exemplary embodiment of  FIGS. 1 and 2 ; 
         FIG. 5  is a perspective oblique view of a retaining body for the attachment system according to a second exemplary embodiment of  FIG. 3 ; 
         FIG. 6  is a perspective view showing the retaining body from  FIG. 5  in the exploded state; 
         FIG. 7  is a side elevational view of an attachment system according to a third exemplary embodiment of the invention; 
         FIG. 8  is a perspective view of the attachment system of  FIG. 7 ; and 
         FIG. 9  is an enlarged, opened, perspective view of a retaining body for the attachment system according to the third exemplary embodiment of  FIGS. 7 and 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a first exemplary embodiment of the invention in its entirety. A base body is in the form of a circular ring body with an inner ring  1  and an outer ring  3 . Distributed around the entire periphery of the outer ring  3 , there is a series of cable bushings  5 , not all numbered in  FIG. 1 . In  FIG. 1 , for example, cables  7  are inserted into only three of the cable bushings  5 . 
     The other cable bushings  5  are shown without the cables inserted for the sake of clarity of the drawings. The inner ring  1  and outer ring  3  are kept at a distance from one another by radially extending braces  9  (only some of which are numbered in  FIG. 1 ). The attachment star formed of the inner ring  1  and outer ring  3  is made as a one-piece injection molding. Details of the configuration of the cable bushings  5  and of the cover interacting with the cable bushings  5  on their openings are shown in  FIGS. 2 and 4 . 
     As  FIG. 2  shows, the cable bushings  5  are formed by trough-shaped bodies  11  (not all numbered in  FIG. 1 ) in the form of troughs which are radially open to the outside and which are connected to one another by wall parts  13 . Wall parts  13  form the axially outside boundary of the outer ring  3 . The cover for the cable bushings  5  has one retaining body  15  for each cable bushing  5  and a single tightening strap or member  17  provided for all cable bushings  5 . Strap  17  extends over the entire outer periphery of the outer ring  3  and, as is conventional for tightening straps, can be tightened by a tensioner  19  actuatable by a clamping screw. 
       FIG. 4  separately shows one of the retaining bodies  15  for the first exemplary embodiment in the form of a one-piece injection molding with a central clamping part  21 . When the retaining body  15  has been moved into the operating position for preliminary fixing of the cable  7  inserted into the pertinent cable bushing  5 , retaining body  15  engages the pertinent cable bushing  5  with one contact surface  23  adjoining the pertinent cable  7 . The top of the retaining bodies  15  opposite the contact surface  23  forms an arched cover surface  25  for contact with the tightening strap  17 , the arch being matched to the peripheral round shape of the outer ring  3 . Laterally from the clamping part  21 , fixing parts  27  are angled relative to the cover surface  25  and have free ends with catch projections  29  facing one another. 
     In the wall parts  13  extending between the trough-shaped bodies  11  on both sides of the trough-shaped bodies  11 , recesses  31  are open radially to the outside. When the retaining bodies  15  are attached, their fixing parts  27  engage the wall part  13 . In the recesses  31 , catches  33  are provided to engage the catch projections  29  of the retaining bodies  15  to lock that motion directed radially to the outside, as a tensioning motion for transfer of the retaining force from the contact surface  23  to the pertinent cable  7 . The retaining bodies are protected against falling out of the cable bushings  5  before the tightening strap  17  is applied. The pertinent cables  7  are therefore fixed beforehand. As the lateral guide for the tightening strap  17 , the wall parts  13  extending between the trough-shaped bodies  11  on the inside form guide surfaces  35  for lateral guidance of the tightening strap  17 . 
     The second exemplary embodiment shown in  FIGS. 3 ,  5 , and  6  differs from the first exemplary embodiment in that the connection between the trough-shaped bodies  11  is formed, not by lateral, axially outside wall parts  13 , but by centrally positioned wall parts  41 . Wall parts  41  at a radial distance from the opening of the trough-shaped bodies  11 , so that the outer sides  43  on the opening edge of the trough-shaped bodies  11  are exposed. As  FIG. 3  clearly shows, on these outer sides  43 , catches  33  are provided for locking to the retaining bodies  15 . In this exemplary embodiment, the retaining bodies  15 , whose shape is detailed in  FIGS. 5 and 6 , with their fixing parts  27  above the edge of the wall parts  41  overlap the outer sides  43  of the trough-shaped bodies  11  for locking engagement of the catch projections  29  with the catches  33 . As  FIGS. 5 and 6  show, the retaining body  15  in this example is made in two parts from identical parts which can be locked to one another by catch strips  45 . 
     In the absence of the axially outer wall parts  13  forming the guide of the tightening strap  17  in the first exemplary embodiment, the cover or outer surface  25  of each retaining bodies  15 , shown separately in  FIGS. 5 and 6 , has radially protruding guide projections  47  for forming the lateral guide surfaces  35  for the tightening strap  17 . 
     To prevent kinking of the tightening strap  17  between the succeeding trough-shaped bodies  11 , bearing pieces  49  on the upper edge of the wall parts  41  are in the gap regions between succeeding trough-shaped bodies  11 . 
     The third exemplary embodiment shown in  FIGS. 7 to 9  is especially well suited for attachment to a flat support structure. Instead of the base body  1  shown above forming a complete, closed, circular ring, in this exemplary embodiment a base body is in the form of a ring part  51  extending over only part of a circular line. The ends of the ring part  51  are connected by a crosspiece integral with the ring part  51  in the form of a straight beam  53 . Beam  53  in turn is screwed to a bracket  55  in the form of a flat steel strip adjoining the underside of the beam  53  over the entire surface. The ends  57  and  59  of the bracket  55  extend beyond the ends of the ring part  51 . Their respective end segments have an offset  61  for support and attachment to a support structure. In proximity to the offsets  61 , the bracket  55  has longitudinal slots  65  used as anchor points for the tensioners  19  for the tightening strap  17  guided over the retaining parts  15  as in the other exemplary embodiments. 
     Another difference of the third exemplary compared to the first and second exemplary embodiments is that the clamping parts  21  of the retaining bodies  15  intended for clamping of the cables  7  are not located rigidly on the retaining bodies. These clamping parts  21  are movably guided in a spring housing  71  and are pretensioned by a spring assembly of several compression springs  63  in the direction to the cable  7  to be clamped. As  FIG. 9  shows, the clamping part  21  has the shape of a rectangular plate. Corner regions guide strips  65  extend from that place into the spring housing  71  and are movably guided therein in guideways or guide  67 . To limit the spring path and to prevent emergence of the clamping part  21  loaded by the spring assembly from the spring housing  71 , stop projections  73  and  75  are on the guides  67  of the housing and the guide strips  65  of the clamping part  21 . As in the above-described exemplary embodiments, the retaining bodies  15  can be secured on the ring part  51  forming the base body for preliminary fixing of the retaining bodies  15 . For this purpose, the corner regions of the spring housing  71  have locking strips  77  corresponding to the fixing parts  27  of the above-described examples and form catch projections  79  correspond to the catch projections  29  of the above-described examples. 
     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.