Abstract:
The invention relates to a guide rail for a window blind of a sliding roof system. The guide rail includes a retaining portion that attaches the guide rail to a vehicle. The guide rail also includes a guide portion that receives the window blind, and a resilient connecting portion which is arranged between the retaining portion and the guide portion.

Description:
[0001]     The application claims priority to German Application No. 10 2004 033 982.1, which was filed on Jul. 14, 2004.  
       BACKGROUND OF THE INVENTION  
       [0002]     The invention relates to a guide rail for a window blind of a sliding roof system for a motor vehicle.  
         [0003]     A window blind of this type may be attached underneath an opening in a vehicle roof in order to cover the opening to a greater or lesser extent at the choice of vehicle occupants. If the opening is to be exposed, the window blind is wound up on a winding shaft. The window blind is uncoiled from the winding shaft to cover the opening. In order to prevent the window blind, when extending underneath the opening in the vehicle roof, from sagging into the vehicle interior space, longitudinal edges of the window blind are received in guide rails so that the window blind can be held taut transverse to a shifting direction of the window blind in the guide rails.  
         [0004]     A specified distance between the guide rails has to be maintained within very narrow tolerances. If this distance is smaller than specified, the window blind sags between the two guide rails into the vehicle interior space. This is undesirable for aesthetical reasons. If this distance between the guide rails is larger than specified, the window blind either can not be shifted within the guide rails at all, or can be shifted only after overcoming very high frictional forces. This adversely affects operability and service life.  
         [0005]     It is the object of the invention to provide an improved guide rail for a window blind that easily meets tolerance demands during manufacturing and/or assembly of the guide rail.  
       SUMMARY OF THE INVENTION  
       [0006]     To this purpose, the subject invention provides a guide rail for a window blind of a sliding roof system. The guide rail includes a retaining portion adapted to attach the guide rail to a vehicle. The guide rail also includes a guide portion that receives the window blind, and a resilient connecting portion which is arranged between the retaining portion and the guide portion.  
         [0007]     The invention provides for an automatic compensation of tolerances in the form of the resilient connecting portion, which is elastic and springy. This makes it possible to design and arrange two guide rails in such a manner that a distance between two guide portions of the two guide rails under any tolerance situation is larger than actually necessary. Once the window blind is inserted into each guide portion of the two guide rails, the two guide portions will be pulled towards each other. During operation, the resilient connecting portion elastically yields without high frictional forces occurring. It is ensured in any case that the window blind is always held taut.  
         [0008]     Preferably provision is made that both the retaining portion and the guide portion are made in one piece with the resilient connecting portion, for instance as an injection-molded part made from plastic. The inherent elasticity of the plastic ensures, in combination with a suitable wall thickness, the required elastic deformability. As an alternative, extruded profiles of plastic or an aluminum alloy can be used.  
         [0009]     These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a vehicle roof comprising a window blind according to the invention;  
         [0011]      FIG. 2  is a schematic side view of a window blind according to the invention; and  
         [0012]      FIG. 3  schematically shows a section along plane III-III of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]      FIG. 1  shows a vehicle including a vehicle roof  5  with an opening  7 . Associated with opening  7  is a cover  9  of a sliding roof system. The cover  9  can be shifted between a closed position in which the cover  9  closes the opening  7 , and an opened position shown in  FIG. 1 .  
         [0014]     A window blind  10  is arranged underneath the cover  9  and also underneath the opening  7 . With regard to the vehicle, the window blind  10  can be moved forwardly and rearwardly by hand or powered by a motor. If the window blind  10  is fully pushed toward the rear of the vehicle, the opening  7  will be entirely exposed. Fresh air and sunlight are able to freely enter a vehicle interior space. If the window blind  10  is fully pushed toward the front of the vehicle, the opening  7  is covered by the window blind  10 . Fresh air and sunlight can enter the vehicle interior space only to a limited extent.  
         [0015]     The window blind  10  is made from a flexible material, for instance from cloth or a plastic film. Provided on a front edge of the window blind  10  is a hoop  12  that can be gripped by a vehicle occupant in order to displace the window blind  10  to the front or to the rear of the vehicle. Two guide rails  14  are laterally spaced apart from each other and extend longitudinally along sides of the opening  7 . Two longitudinal edges of the window blind  10 , i.e. right and left edges of the window blind  10  as seen in a longitudinal direction of the vehicle, are received in these guide rails  14 . In an area of a rear end of the opening  7  there is disposed a winding shaft  16  (see  FIG. 2 ) on which the window blind  10  can be wound up. The winding shaft  16  is usually biased by a spring, so that the window blind  10  will be automatically received on the winding shaft  16  when the hoop  12  is pushed towards the rear.  
         [0016]     Each window blind  10  has a guide element  18  along the longitudinal edges, i.e. in the area associated with the guide rails. The guide element  18  is configured as a thin strip made of metal or plastic.  
         [0017]     Each guide rail  14  (see in particular  FIG. 3 ) has a retaining portion  20 , a guide portion  22  and a connecting portion  24 . The retaining portion  20  serves for fastening the guide rail  14  to the vehicle roof  5 , for example at an edge portion of a rail  21  for guiding the cover  9 . Here, the retaining portion  20  has a retaining ledge  26  and a latching hook  28  that makes it possible to mount the guide rail  14  to the rail  21  that guides the cover  9  with low effort.  
         [0018]     The guide portion  22  serves for receiving and guiding the guide element  18  of the window blind  10 . To this end, the guide portion  22  is provided with an upper guide web  30  and a guide web  32  directed towards the vehicle interior space.  
         [0019]     The connecting portion  24  extends between the retaining portion  20  and the guide portion  22  and is provided here with a semicircular cross-section at an upper end as shown in  FIG. 3 . The connecting portion  24  is also provided with a connecting web  34  that extends towards the guide portion  22 . The connecting portion  24  is configured such that in an initial state the retaining portion  20  and the guide portion  22  have a smaller distance between them (see, in broken line, the position  22 ′ of the guide portion  22 ) than in a condition when the window blind  10  is between the two guide rails  14 .  
         [0020]     If the window blind  10  is withdrawn from the winding shaft  16  and shifted to the front in the guide portions  22 , the guide portions  22  will be drawn from their initial position towards each other whereby the window blind  10  is held taut. Due to the elasticity of the connecting portion  24  of the two guide rails  14 , the tensional forces exerted on the window blind  10  remain on a relatively low level, so that only low frictional forces occur between the guide elements  18  of the window blind  10  and the guide portions  22  of the guide rails  14 . Spring forces exerted by the connecting portions  24  can be adjusted on the one hand by geometry and material. On the other hand, spring forces can be adjusted by suitably selecting a wall thickness to influence spring force, for instance by local thickness reductions at the connecting portion  24  as indicated in broken lines in  FIG. 3 .  
         [0021]     Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.