Abstract:
A roller blind system for a vehicle roof includes a rotatable coiling body and a roller blind that is attached at one end to the coiling body and at the other end to a vehicle portion in a stationary manner. The coiling body is shiftable in a translational motion, allowing the roller blind to uncoil and coil up while minimizing frictional forces on the roller blind.

Description:
REFERENCE TO RELATED APPLICATIONS 
   The present invention claims the benefit of German Patent Application No. 102 56 599.6, filed Dec. 4, 2002. 
   TECHNICAL FIELD 
   The invention relates to a roller blind system, in particular for a motor vehicle, comprising a coiling body that is rotatable and a roller blind that is attached at one end to the coiling body. 
   BACKGROUND OF THE INVENTION 
   Various designs of roller blind systems for vehicles are known. German Published Patent Application 197 39 919, for example, discloses a roller blind system in which a coiling body is mounted at an edge of an opening in a vehicle roof. The roller blind may be withdrawn from the coiling body so that the roller blind extends across the area of the opening to constitute a sunshade in this area. The roller blind is laterally guided by a pair of guide rails into which the longitudinal edges of the roller blind are inserted when the blind is withdrawn from the coiling body. 
   The disadvantage of this structure is that the forces for actuating the roller blind rise super-proportionally when the blind is withdrawn from the coiling body. First, there is in fact an increase in a retracting force that is exerted on the coiling body by a retracting spring. Additionally, a frictional force is produced by friction between the edges of the roller blind and the guide rails and increases as the withdrawal length of the roller blind increases. 
   One object of the invention to further develop a roller blind of the type mentioned above that reduces the increase in the actuating forces as an increasing amount of the roller blind is withdrawn. 
   SUMMARY OF THE INVENTION 
   Accordingly, one embodiment of the invention is directed to a roller blind system having one end secured to a coiling body and its opposite end mounted to the vehicle so that it is stationary. The coiling body is adapted to be shifted by a translational motion. This roller blind system is based on the fundamental concept that the friction between the guide rails and the roller blind occurring in prior art systems can be avoided by having the coiling body perform a translational motion. As a result, the roller blind remains stationary and is uncoiled across the area which it is intended to cover. This uncoiling is conducted instead of withdrawing the roller blind from the coiling body, which would result in an even longer area of the roller blind needing to be shifted. 
   In accordance with one embodiment of the invention, the system may include two guide rails that releasably connect two longitudinal edges of the roller blind. This allows the guide rails to receive the roller blind firmly at its edges in a manner similar to that known in the prior art, with the roller blind in the roller blind system according to the invention being stationarily connected with the guide rail at a multitude of points when the coiling body is moved in relation to the guide rail. In a particularly simple embodiment, the guide rail and the associated longitudinal edge of the roller blind are provided with two mating parts of a VELCRO® fastener. This allows stationary attachment of the roller blind to the two guide rails when the coiling body is moved along the guide rails. 
   According to one embodiment of the invention, each longitudinal edge of the roller blind has a detent part that may be connected with a counterpart fitted to or integrated into the guide rail. The longitudinal edges of the roller blind are thus fitted to the guide rails with an interlocking fit when the coiling body moves along the guide rails. 
   The two guide rails may be configured so they are parallel to each other to accommodate a rectangular roller blind. It is further possible for the two guide rails to be disposed at a variable distance from each other and for the roller blind to have a variable width such that the two longitudinal edges of the roller blind follow the course of the guide rails. In this arrangement, the guide rails may extend in a straight line while being inclined with respect to each other or they each may be curved. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described with reference to different embodiments illustrated in the accompanying drawings in which: 
       FIG. 1  shows a schematic diagram of a roller blind system in accordance with a first embodiment of the invention; 
       FIG. 2  shows a schematic diagram of a roller blind system in accordance with a second embodiment of the invention; 
       FIG. 3  shows a schematic diagram of a roller blind system in accordance with a third embodiment of the invention; 
       FIG. 4  shows a diagrammatic top view of a roller blind system in accordance with the first embodiment; 
       FIG. 5  shows the section V—V of  FIG. 4  on an enlarged scale; and 
       FIG. 6  shows a diagrammatic sectional view of a variant of a roller blind system in accordance with the first embodiment. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
     FIG. 1  diagrammatically shows a roller blind system  10  having a coiling body  12  and a roller blind  14 . One end of the roller blind  14  is firmly secured to the coiling body  12  while the opposite end is mounted to the vehicle to be stationary. This stationary mounting surface is symbolized in  FIG. 1  by a vehicle portion  16 . The roller blind system  10  is fitted below a roof  18  of a motor vehicle having a roof opening  20 . The roof opening  20  may be closed by a cover (not shown) of a sliding roof system. 
   The coiling body  12  is usually accommodated within a cartridge (not shown) and may be shifted below the roof opening  20  by a translational motion. When the coiling body  12  is shifted to the left in the direction of the arrow P shown in  FIG. 1 , the roller blind  14  extends beneath the roof opening  20  to form a sunshade. 
     FIG. 2  shows a roller blind system having two coiling bodies  12 . One roller blind  14  is received on each coiling body  12 , and the two roller blinds  14  are connected to each other. In this example, the two roller blinds  14  are fixedly secured to the vehicle portion  16  at the juncture between the two blinds  14 . The two coiling bodies  12  may be shifted in opposite directions to each other so that, for instance, a front roof opening and a rear roof opening of a vehicle roof may be respectively covered by the two roller blinds. 
     FIG. 3  shows a roller blind system which, similar to the roller blind system shown in  FIG. 2 , comprises two roller blinds  14  that are received on two coiling bodies  12 . Unlike the roller blind system of  FIG. 2 , the roller blind system of  FIG. 3  does not connect the two roller blinds with each other. Instead, the two roller blinds  14  are respectively connected to two opposing vehicle portions  16 . The two opposing coiling bodies  12  may be brought together toward the center so that, for instance, a front and a rear roof opening may be respectively covered by the two roller blinds. 
     FIGS. 4 and 5  show a roller blind system corresponding to the structure illustrated in  FIG. 1 . Like reference numerals are used for like components described with respect to  FIG. 1 , and in this respect reference is made to the foregoing discussions. 
   The roller blind system includes two guide rails  22  that extend along the longitudinal edges of the roof opening  20 . At the top end in  FIG. 4 , the two guide rails  22  are connected by a crosspiece, which corresponds to the stationary vehicle portion  16  described above, where one end of the roller blind  14  is fastened. 
   Each guide rail  22  has a guide groove  24  ( FIG. 5 ) in which a sliding carriage  26  is guided. An arbor  28  of the coiling body  12  is received in the sliding carriage  26 . A pretensioning spring  30  connected to the arbor  28  urges the coiling body  12  toward a base section  32  of the guide rail  22 . The base section  32  has a counterpart, such as a detent web  34 , formed thereon and having a dovetailed cross-section. 
   The roller blind  14  is received on the coiling body  12 , with two thicknesses thereof being shown in this arrangement. Each longitudinal edge of the roller blind  14  is provided with a clip  36  ( FIG. 5 ), which may be made of plastic and has an inside cross-section shaped to be complementary to the dovetailed cross-section of the detent web  34 . The roller blind  14  may be molded into the clip  36 , for example. The material of the clip  36  is flexible so that the roller blind, along with the two clips, may be received at its longitudinal edges on the coiling body  12 . 
   When the coiling body is shifted downward in regard to  FIG. 4  and along the guide rails  22 , the roller blind  14  is uncoiled from the coiling body  12  which, assisted by the pretensioning spring  30 , presses the clip  36  onto the detent web  34  so that the clip  36  is gradually locked into place on the detent web  34  with an interlocking fit. This results in reliable lateral guidance of the roller blind  14  in the area between the coiling body  12  and the vehicle portion  16 . 
   Note that any other suitable detent mechanism may be used instead of the interlocking clip  36  and detent web  34 . The detent mechanism may be any mechanism made up of a detent part and a counterpart adapted to be releasably connected with each other when the coiling body is moved along the two guide rails  22  without departing from the scope of the invention. 
     FIG. 6  illustrates another embodiment that differs from the embodiment shown in  FIGS. 4 and 5  with respect to the way the roller blind  14  is connected with, and released again from, the guide rail. 
   In this embodiment, the coiling body  12  is mounted on the sliding carriage  26  to be non-displaceable. In this embodiment, the sliding carriage  26  is a cartridge having the roller blind  14  received therein and includes a pressure slider  38  that is elastically pretensioned so that it rests on the detent web  34  with a certain degree of pretension. The roller blind  14  or the clip  36  in this embodiment may be located between the pressure slider  38  and the detent web  34 . The sliding carriage  26  further includes a release slider  40  arranged between the roller blind  14  or the clip  36  fitted thereto and the detent web  34 . The roller blind  14  accordingly exits the cartridge between the pressure slider  38  and the release slider  40 . 
   When the sliding carriage  26  is shifted such that the roller blind  14  is withdrawn from the sliding cartridge  26 , the pressure slider  38  presses the clip  36  onto the detent web  34  so that it is locked in place. When the sliding carriage  26  is shifted in the opposite direction so that the roller blind  14  is received on the coiling body  12 , the release slider  40  will move between the clip  36  and the detent web  34  so that the roller blind  14  is released from the guide rail  22  to be coiled up. 
   It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby.