Abstract:
Components must often be released again from their holder for maintenance. Since the fastenings are often very complicated, it takes a considerable amount of time to release them. A fastening system is one where components can be fastened in a rotationally locked manner to a holder, and released again in a simple, reliable and quick manner.

Description:
The present application hereby claims priority under 35 U.S.C. §119 on European patent application number EP 02018487.5 filed Aug. 16, 2002, the entire contents of which are hereby incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention generally relates to a fastening system for a component. In particular, it relates to a fastening system for a turbine guide blade. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 5,540,552 shows a turbine blade which is fastened at two points to a holder. Namely, it is fastened on the rotor of a turbine. A bayonet coupling is used at one point. 
     U.S. Pat. No. 5,074,752 shows a turbine guide blade which is fastened at both ends, one end having a bayonet coupling. The turbine guide blade cannot be rotated. 
     U.S. Pat. No. 5,244,345 shows how a safety mat is secured to a disk of a turbine rotor by way of a bayonet coupling. 
     SUMMARY OF THE INVENTION 
     An object of an embodiment of the invention is to show a fastening system by which a component can be releasably fastened to a holder in a quick, reliable and simple manner. 
     An object may be achieved by a fastening system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the invention is shown simplified in drawings. 
       In the drawings: 
         FIG. 1  shows a fastening system according to an embodiment of the invention, 
         FIG. 2  shows a tube element of a fastening system according to an embodiment of the invention, 
         FIG. 3  shows an underside of a turbine blade as a component which is fastened by the fastening system according to an embodiment of the invention, 
         FIG. 4  shows a bolt of a fastening system according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a fastening system  4  according to an embodiment of the invention, having a component  1 , in particular a turbine guide blade  1 , and a holder  7 , to which the component  1  is fastened. The component  1  is fastened to the holder  7 , for example, only with the fastening system  4  and extends in a radial direction  3 . 
     The holder  7  is, for example, part of a casing, for example of a turbine, or part of a guide blade carrier. The holder  7  has a continuous opening  19  which extends continuously in radial direction  3  from an outside  70  of the holder  7  to an inside  73  and, for example, is of circular design in cross section perpendicularly to the axis  3 . 
     An intermediate piece  13 , for example a tube element  13 , is arranged in the continuous opening  19 , and a bolt  10  is arranged in the tube element  13 . The component  1  is fastened to the tube element  13  by way of a bayonet catch ( FIGS. 2 ,  3 ). The tube element  13  serves to hold the turbine guide blade  1  in the radial direction  3 . 
     The bolt  10 , with its shaped elements—a bolt projection  22  and a bolt lug  25 —serves as an anti-rotation locking means for the component  1  relative to the tube element  13 . A retaining cap  28 , for example a screw  28 , on the outside  70  prevents both the bolt  10  and the tube element  13  from being able to move out of the continuous opening  19 . The tube element  13  rests with its retaining collar  55 , for example inside the continuous opening  19 , on a support step  40 . Further means of fastening the tube element  13  to the holder  7  are conceivable. 
     The turbine guide blade  1  can be pushed, for example, from the outside  70  completely through the continuous opening  19 ; i.e. a maximum cross-sectional area  41  of the component  1  fits in its shape through a minimum cross-sectional area  42  of the continuous opening  19 . As viewed in radial direction  3 , the continuous opening  19  narrows where the support step  40  is present. 
       FIG. 2  shows the tube element  13  of  FIG. 1 . Inside the tube element  13  is an interior space  14  which extends continuously in radial direction  3  and, for example, is of circular design in cross section perpendicularly to the direction  3 . 
     The bolt  10  ( FIG. 4 ) is arranged inside the interior space  14 . The bolt  10 , with its at least one bolt projection  22  ( FIG. 4 ), comes to bear in a positive-locking manner in a shaped element  37  corresponding to the shaped element  22 , for example a receptacle  37 , inside the interior space  14  in the vicinity of the outside  70 , so that the bolt  10  cannot be rotated relative to the tube element  13 . The receptacle  37  is, for example, a notch on an inner surface of the interior space  14 . The tube element  13  therefore has a larger inside diameter, for example, in the region of the outside  70  than in the deeper-situated region of the receptacle  37 . 
     In the radial direction  3  as viewed toward the interior space  73  of the turbine, there is a constriction  11  in the outer dimensions, for example in the diameter, of the tube element  13 , so that the retaining collar  55  is formed there. 
     There is then in turn partly a widened portion  12  at its radial end. This widened portion  12  extends in the circumferential direction around the tube element  13 . The widened portion  12  is formed in the shape of a ring segment on the tube element  13  and represents the one of two coupling sides of a fastening system  4  ( FIG. 1 ). The widened portions  12  are designed in such a way that the L-shaped steps  20  ( FIG. 3 ) of the component  1  can enclose them. 
       FIG. 3  shows the underside of the component  1  (e.g. turbine blade), the second coupling side  16  of the fastening system  4  being formed on this underside. On the underside of the component  1 , which bears against the holder  7 , there is a shaped element  34  corresponding to the shaped element  25 , for example a recess  34 , in which the correspondingly shaped bolt lug  25  ( FIG. 4 ) engages in a positive-locking manner in such a way that the bolt lug  25  cannot rotate in the receptacle  34 . 
     As viewed in the circumferential direction around the radial axis  3 , L-shaped steps  20  are formed on the underside of the component  1 . The L-shaped steps  20  have at least one lead-through  17 , into which the widened portions  12  of the tube element  13  fit. The L-shaped steps  20  are designed in such a way that the component  1  can be rotated in such a way that the widened portions  12  can be arranged bayonet-like inside the L-shaped steps  20 . After it has been appropriately rotated, the turbine blade  1  is held in radial direction  3  by the L-shaped steps  20  and the widened portions  12 . 
       FIG. 4  shows the bolt  10 , which bears against both the tube element  13  and the component  1  and serves for the anti-rotation locking of component  1  and tube element  13 . The tube element  13  is, for example, part of an adjusting device, i.e. the tube element  13  can be rotated about its longitudinal axis disposed in radial direction  3 , so that the component  1  can be rotated with it in the same way in order to adjust the component  1 , for example the turbine guide blade  1 , relative to a flowing medium in a gas turbine. Likewise, however, it is also possible for the tube element  13  to be arranged in a rotationally locked manner inside the holder  7 . 
     The assembly of the turbine blade  1  and the holder  7  with the fastening system  4  is effected, for example, as follows. 
     The component  1  is pushed from outside  70  through the continuous opening  19  or from inside  73  into the continuous opening  19 . The tube element  13  is then likewise pushed into the continuous opening  19  until it bears with the retaining collar  55  against the support step  40 , and is then connected to the component  1 . 
     After that, the bolt  10  is inserted into the tube element  13 , so that the bolt lug  25  rests in the receptacle  34  of the component  1  and the bolt projection  22  rests in the recess  37  of the tube element  13 . However, it is also possible for the elements ( 1 ,  10 ,  13 ) to already be assembled before being pushed through or into the continuous opening  19 . Finally, the screw  28  is fitted. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.