Patent Publication Number: US-2016236549-A1

Title: Cover system for a load bed of a vehicle, and vehicle having a cover system of this type

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This claims the benefit of U.S. Provisional Application No. 62/115,772, filed Feb. 13, 2015. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a cover system for a load bed of a vehicle having a winding shaft which is rotatably mounted in a support structure, having a flexible flat structure which is mounted such that it can be wound up and unwound on the winding shaft between a rest position and a covering position, and which is connected to a dimensionally stable pull-out profile on its front end region which lies away from the winding shaft, and having two guide rail arrangements on opposite sides of the flat structure, in which the pull-out profile is guided longitudinally displaceably. 
     In addition, the invention relates to a vehicle having a load bed which is open at the top and is delimited on all sides by walls which protrude upward from the load bed, and having a cover system which has a flexible flat structure for covering the load bed at least partially, which flat structure is mounted on a winding shaft which is mounted rotatably on the vehicle side such that said flat structure can be moved between a covering position, in which it is pulled off from the winding shaft, and a rest position, in which it is wound onto the winding shaft, and which flat structure is provided with a dimensionally stable pull-out profile on a front end region in the pull-out direction. 
     BACKGROUND OF THE INVENTION 
     DE 199 44 948 C1 has disclosed a passenger station wagon having a load space which is arranged in a vehicle interior and is provided with a cover system in the form of a load space covering. The cover system has a covering tarpaulin which is mounted on a winding shaft such that it can be wound up and unwound. The winding shaft is mounted rotatably in a cassette housing which is mounted in a fixed manner on the vehicle. On its front end region in the pull-out direction, the covering tarpaulin has a dimensionally stable pull-out profile which is held with its front end regions which lie opposite one another in driving slides which are mounted such that they can be displaced longitudinally in guide rails which are arranged in a fixed manner on the vehicle. In the winding-up direction, the winding shaft is loaded with a torque by way of a coil spring arrangement. In the pull-out direction, in contrast, a drive system is active which comprises an electric motor which is arranged fixedly on the vehicle. The electric motor drives the driver slides synchronously with respect to one another via two flex-shafts and displaces said driver slides within the guide rail arrangements. The displacement by way of the electric motor takes place in the pull-out direction counter to the restoring force of the coil spring arrangement which is integrated into the winding shaft. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a cover system and a vehicle of the type mentioned at the outset which are improved in comparison with the prior art. 
     This object is achieved for the cover system by virtue of the fact that the flat structure is reinforced in a manner which is distributed over its length by a plurality of transverse bows which extend in each case over an entire width of the flat structure and are guided on their end sides which lie opposite one another in the guide rail arrangements which lie opposite one another. The transverse bows make particularly satisfactory stability of the flat structure possible in its pulled-out covering position. The cover system according to the invention can therefore be used in a particularly advantageous way for open load beds of pickup vehicles. This is because the flat structure remains in its covering position independently of wind or weather influences even during driving operation of a corresponding pickup vehicle as a result of the high stability of the flat structure with the aid of the transverse bows. The invention is used for load beds which are open toward the surroundings, that is to say they are exposed to ambient influences such as wind and water or snow and ice. 
     The solution according to the invention is suitable in a particularly advantageous way for an open load bed of a pickup passenger motor vehicle. In the same way, the cover system according to the invention can also be used for open load beds of other wheeled or tracked vehicles or of rail vehicles. 
     In one refinement of the invention, the transverse bows are arranged above or below the flat structure and are fastened to the flat structure by means of at least one weather strip connection which is extended over the length of the respective transverse bows. Accordingly, depending on the arrangement of the transverse bows, the transverse bows reinforce the flat structure visibly or invisibly. There is a visible reinforcement if the transverse bows are arranged above the flat structure, with the result that they are visible on an outer side of the flat structure. In the case of an arrangement of the transverse bows below the flat structure, the transverse bows are provided invisibly in the region of an inner side of the flat structure, which inner side faces a floor of the load bed in the covering position of the flat structure. 
     In a further refinement of the invention, the transverse bows have a convexly curved cross-sectional profile. The convexly curved cross-sectional profile ensures particularly high longitudinal stiffness of the transverse bows, with the result that the flat structure is reinforced reliably even over a relatively large width. This is advantageous if the cover system is used in a pickup passenger motor vehicle, the load bed of which, as viewed in the vehicle transverse direction, has a relatively large width. The flat structure can preferably be pulled out or wound up in the vehicle longitudinal direction and the transverse bows extend in the vehicle transverse direction. 
     In a further refinement of the invention, in order to guide each transverse bow in the guide rail arrangements which lie opposite one another, in each case one sliding body is provided on the end sides of the transverse bow which lie opposite one another, which sliding body is mounted such that it can be moved slidingly in the longitudinal direction of the guide rail arrangement in each case one guide groove of the respective guide rail arrangement. As a result, each transverse bow is supported directly in the guide rail arrangements which lie opposite one another, as a result of which sagging of the flat structure in the pulled-out covering position is avoided reliably. 
     In a further refinement of the invention, the sliding bodies are held in the end sides of the transverse bow with the aid of complementary plug-in profiles. Both the transverse bows and the sliding bodies are preferably manufactured from plastic materials. The refinement makes particularly simple mounting of the sliding bodies in the end sides of the transverse bow possible. As plug-in profiles which are complementary with respect to one another, the sliding bodies can be provided with plug-in journals and the end sides of the transverse bow can be provided with complementary plug-in sockets. 
     In a further refinement of the invention, the flat structure is provided on its longitudinal edges which lie opposite one another in each case with lateral guide elements which are held in a positively locking manner transversely with respect to the pull-out direction in a lateral guide channel of the respective guide rail arrangement. The lateral guide elements are provided so as to run longitudinally in a row or in a line on the longitudinal edges of the flat structure which lie opposite one another, and are threaded into the respective lateral guide channel of the guide rail arrangements which lie opposite one another, in order thus to make secure retaining of the longitudinal edges of the flat structure possible transversely with respect to the pull-out direction in the guide rail arrangements which lie opposite one another. The longitudinal edges of the flat structure which lie opposite one another run, as viewed in the pull-out direction of the flat structure, on opposite sides of the flat structure. The lateral guide elements are formed in an advantageous way by bead or knob parts which are connected fixedly to the longitudinal edges. The corresponding bead or knob parts are preferably arranged one behind another at uniform spacings in a row along the respective longitudinal edge. The cross sections of the bead or knob parts are greater than a width of a corresponding longitudinal slot of the respective lateral guide channel in the guide rail arrangements which lie opposite one another, with the result that the desired positively locking retention transversely with respect to the pull-out direction of the flat structure is ensured. The lateral guide elements make a taut arrangement of the flat structure possible transversely with respect to its pull-out direction even in the pulled-out covering position. This is advantageous in the case of wind and weather influences which can have a pronounced effect on the cover system, in particular, during driving operation of a pickup passenger motor vehicle. This is because the lateral guide elements reliably prevent the flat structure from being torn out of the lateral guide rail arrangements in its covering position, in which it covers the load bed. 
     In a further refinement of the invention, the transverse bows are arranged at a spacing from one another in the longitudinal direction of the flat structure in such a way that the transverse bows in the region of the winding shaft can be wound up in the circumferential direction in different winding layers in an offset manner between transverse bows of in each case one winding layer which lies underneath. As a result, particularly compact winding up of the flat structure can be achieved, as a result of which the support structure which mounts and surrounds the winding shaft can also have relatively compact dimensions. 
     In a further refinement of the invention, deflection means which are arranged in a stationary manner are provided in a winding region of the flat structure, which deflection means deflect the transverse bows toward the winding shaft in such a way that the transverse bows can be wound up in an oriented manner such that their convex curvature is adapted relative to the winding shaft. This refinement also makes particularly compact winding of the flat structure onto the winding shaft possible. 
     The object on which the invention is based is also achieved in a cover system of the type mentioned at the outset by virtue of the fact that a cleaning strip is provided in a winding region of the flat structure, which cleaning strip is extended parallel to a rotational axis of the winding shaft and is oriented relative to the flat structure in such a way that, during a winding operation onto the winding shaft or an unwinding operation from the winding shaft, a surface of the flat structure slides past the cleaning strip such that it makes contact. The cleaning strip can be provided with a brush surface or a surface which is provided with other mechanical cleaning means. As a result of the contact of the surface of the flat structure with the cleaning strip when sliding past, the surface of the flat structure is necessarily cleaned. The cleaning strip preferably extends continuously over the entire width of the flat structure, with the result that a uniform cleaning function of the entire flat structure is made possible during a winding-up and/or unwinding operation. The cleaning strip is preferably arranged in a stationary manner. However, according to one embodiment of the invention, it can also be arranged movably and can preferably be pressed by way of spring forces against the surface of the flat structure. The winding-up region of the flat structure is to be understood to mean the spatial region between the guide rail arrangements and the winding shaft, on which the flat structure is released from the longitudinally running extent between the guide rail arrangements, is deflected and is wound onto the winding shaft. 
     For the vehicle, the object on which the invention is based is achieved by virtue of the fact that the pull-out profile is assigned an elastic hollow profile seal which is extended over an entire width of the flat structure and terminates sealingly with a wall of the load bed in the covering position of the flat structure. As a result, a largely water-tight and/or air-tight closure between the wall of the load bed and the flat structure can be achieved in the covering position of the flat structure. The wall is preferably a rear-side wall of the load bed, with the result that the elastic hollow profile seal produces a sealed rear closure of the covering system in the pulled-out covering position of the flat structure. 
     In one refinement of the invention, the hollow profile seal has a water discharge lug which extends over an entire length of the hollow profile seal and which protrudes beyond the wall of the load bed in the covering position of the flat structure. The water discharge lug ensures that water which strikes the flat structure from above is guided away beyond the correspondingly adjacent wall of the load bed of the vehicle. This refinement therefore avoids water being able to penetrate between a corresponding rear-side closure of the flat structure and a corresponding rear wall of the load bed of the vehicle into a load space below the flat structure in the region of the load bed. 
     In a further refinement of the invention, a wall is cut out at least in sections, in order to receive a cassette housing of the cover system in a flush manner, which cassette housing serves as support structure. This ensures particularly compact and integral accommodation of the cover system in the region of the load bed of the vehicle. In a particularly advantageous way, the vehicle is configured as a pickup passenger motor vehicle. The wall is preferably a front-side wall of the load bed, with the result that the flat structure is pulled out from front to rear to a rear-side wall of the load bed in order to transfer it from the rest position into the covering position, with which rear-side wall of the load bed the elastic hollow profile seal terminates sealingly in the pulled-out covering position of the flat structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages and features of the invention result from the claims and from the following description of one preferred exemplary embodiment of the invention which is shown using the drawings, in which: 
         FIG. 1  diagrammatically shows a pickup passenger motor vehicle with one embodiment of a cover system according to the invention for the load bed of the pickup, 
         FIG. 2  shows the cover system according to  FIG. 1  in a completely pulled-out covering position, 
         FIG. 3  shows a greatly enlarged, diagrammatic cross-sectional illustration of a part region of a flat structure of the cover system according to  FIG. 2  in the region of a transverse bow, 
         FIG. 4  shows a further embodiment of a flat structure for a cover system according to  FIG. 2  in a cross-sectional illustration with a transverse bow which lies on the outside, 
         FIG. 5  diagrammatically shows a sectional illustration of a rear-side closure of the load bed, a pull-out profile of the flat structure being provided with an elastic hollow profile seal, 
         FIG. 6  diagrammatically shows a sectional illustration of a winding-up region of a winding shaft of the cover system according to  FIGS. 1 to 5 , 
         FIG. 7  diagrammatically shows the winding up of a flat structure, provided with transverse bows, of the cover system according to  FIGS. 1 to 6  in a partially wound-up state, 
         FIG. 8  diagrammatically shows a cross section through a guide rail arrangement of the cover system according to  FIGS. 1 and 2  in the region of a side wall of the load bed of the pickup, 
         FIG. 9  shows a detail of the cover system according to  FIGS. 1 to 8  in the region of the guide rail arrangement according to  FIG. 8 , 
         FIG. 10  shows an exploded illustration of a part region of the cover system according to  FIGS. 1 to 9 , 
         FIG. 11  shows an enlarged exploded illustration of an end side of a transverse bow of a flat structure of the cover system according to  FIG. 10 , 
         FIG. 12  shows a perspective sectional illustration of a detail of the cover system in the region of a guide rail arrangement which lies opposite the guide rail arrangement according to  FIG. 9 , 
         FIG. 13  diagrammatically shows the guide rail arrangement according to  FIG. 12  in a cross-sectional illustration with an illustration of a lateral guide function for the flat structure, 
         FIG. 14  shows the illustration according to  FIG. 13  with an additional pictorial illustration of a water discharge function, 
         FIG. 15  shows an exploded illustration of the guide rail arrangement according to  FIGS. 12 to 14  with a covering section and a structure section, 
         FIG. 16  shows the opposite guide rail arrangement according to  FIGS. 8 and 9  in an exploded illustration, in which a spring clamping element for fixing the covering section on the structure section can be seen, 
         FIG. 17  diagrammatically shows a longitudinal sectional illustration through a winding shaft of the cover system according to  FIGS. 1 to 16 , which winding shaft is provided with an electric drive system, and 
         FIG. 18  shows the drive system for the winding shaft according to  FIG. 17  in an exploded illustration. 
     
    
    
     DETAILED DESCRIPTION 
     A wheeled vehicle in the form of a pickup passenger motor vehicle  1  has a passenger cell with front and rear seats in a front region. Toward a rear of the pickup passenger motor vehicle, the passenger cell is adjoined by a load bed  2  which is delimited on all sides by upwardly protruding walls  3  to  5 . The load bed  2  has a substantially horizontal load floor. A front wall  5  which is extended in the vehicle transverse direction, is guided upward at a right angle with respect to the load floor and is arranged immediately behind the passenger cell protrudes on the front side from the load floor. Opposite longitudinal sides of the load bed  2  are formed by two side walls  4  which are extended in the vehicle longitudinal direction and likewise protrude upward from the load floor. The side walls  4  open on the rear side into a rear wall  3  which is extended in the vehicle transverse direction and forms a rear-side termination of the load bed  2  which is open at the top. The rear wall  3  is provided in a manner which is not shown with a tailgate which can be folded rearward and downward, in order to make rear-side access to the load bed  2  possible. 
     In order for it to be possible to close the load bed  2  in an upper edge region of the walls  3  to  5 , a cover system  6  is provided which will be described in greater detail in the following text using  FIGS. 2 to 18 . The cover system  6  has a tarpaulin-like, flexible flat structure  7  which is held on a winding shaft  16  such that it can be wound up and unwound. The winding shaft is mounted rotatably in a cassette housing  8  which serves as support structure, the cassette housing  8  being mounted in the region of the front wall  5  in the mounted state in the region of the load bed  2  of the pickup passenger motor vehicle  1 . To this end, the front wall  5  has a cutout which is indicated in  FIG. 1  and into which the cassette housing  8  is inserted in a flush manner. In the mounted operating state of the cover system  6 , the winding shaft  16  and therefore also the cassette housing  8  extend in the vehicle transverse direction over a width of the load bed  2 . 
     Two guide rail arrangements  9  which are connected to the front end regions of the cassette housing protrude parallel to one another from opposite front end regions of the cassette housing  8  in the pull-out direction of the flat structure  7 . In the mounted operating state of the cover system  6 , the guide rail arrangements  9  protrude rearward in the vehicle longitudinal direction from the cassette housing  8  as far as toward the rear wall  3 , the guide rail arrangements  9  flanking the flat structure  7  on its longitudinal sides which lie opposite one another. 
     As can be seen using  FIG. 8 , each guide rail arrangement  9  is connected fixedly via at least one fastening fitting  23  and corresponding fastening screws  24  to the corresponding side wall  4  of the load bed  2 . Here, first of all the respectively corresponding fastening fitting  23  is fastened to the side wall  4  by way of corresponding fastening screws  24 , before subsequently the guide rail arrangement  9  is placed onto the at least one fastening fitting and is connected to the latter via floor-side fastening screws  24 . The cassette housing  8  and the guide rail arrangements  9  form the stationary sections of the cover system  6 , which stationary sections are connected fixedly via corresponding mechanical fastening means, such as, in particular, the fastening fittings  23 , to the walls  4 ,  5  of the load bed  2  of the pickup passenger motor vehicle  1 . 
     The flexible flat structure  7  which is formed by a single-layer or multiple-layer textile or film web is reinforced over its length by way of a plurality of transverse bows  10 ,  10   a  which are positioned at uniform spacings from one another. The transverse bows  10 ,  10   a  have a convexly curved, arcuate cross-sectional profile, as can be seen clearly using  FIGS. 3 to 7 . The transverse bows  10 ,  10   a  are of dimensionally stable design and extend over an entire width of the flat structure  7  in the vehicle transverse direction, in relation to the mounted operating state of the cover system  6 . The transverse bows are oriented relative to the flat structure  7  in such a way that the convex curvature of the transverse bows  10 ,  10   a  protrudes upward in the horizontally pulled-out covering position of the flat structure  7  ( FIG. 2 ), whereas the correspondingly concave curvature protrudes toward the load floor of the load bed  2 . All the transverse bows  10  are connected in a positively locking manner via weather strip connections  12 ,  13  to the flat structure  7 . To this end, corresponding connecting sections  7 ′ which extend in each case over a width of the flat structure  7  have in each case one weather strip  13  which is pulled into in each case one weather strip groove  12  which is extended in the longitudinal direction of the transverse bows  10 ,  10   a , and therefore in the vehicle transverse direction in the mounted state. The connecting sections  7 ′ of the flat structure  7  are connected fixedly to the flat structure  7  in the region of seams  140 ,  140 ′, in particular by way of welding, sewing or in another way. 
     As can be seen using  FIGS. 3 to 7 , two different variants are provided, in order to reinforce the flat structure  7  by way of the transverse bows  10 ,  10   a  transversely with respect to the pull-out direction. In the embodiment according to  FIGS. 3 and 6 , the transverse bows  10   a  are arranged in the region of an underside of the flat structure  7 , that is to say on a side of the flat structure  7  which faces the load floor of the load bed  2 . To this end, the connecting sections  7 ′ are connected fixedly in the region of seams  140  to the flat structure  7 . The connecting sections  7 ′ are guided on the outside around the convex curvature of the transverse bow  10   a  and are fixed in a positively locking manner in two lateral weather strip grooves  12  with the aid of corresponding weather strip cords  13 . 
     In the embodiment according to  FIGS. 4, 5 and 7 , the connecting sections  7 ′ are fastened via seams  140 ′ in the region of an upper side of the flat structure  7  and, including a common weather strip cord  13 , protrude upward from the upper side of the flat structure  7 . In this variant, the corresponding transverse bow  10  is positioned visibly on the upper side of the flat structure  7  and is connected in a positively locking manner via a middle, centrally arranged weather strip groove  12  to the connecting sections  7 ′ and the weather strip cord  13  of the weather strip connection. 
     Each transverse bow  10 ,  10   a  is manufactured as a dimensionally stable hollow profile made from metal or from plastic, preferably in an extrusion process or an injection molding process. 
     All the transverse bows  10 ,  10   a  are designed identically to one another. A transverse bow  10  ( FIGS. 2 and 5 ) which is arranged on the end side in the pull-out direction on a front end region of the flat structure  7  is additionally provided on a longitudinal side which lies away from the flat structure  7  with a hollow profile seal  11  which extends over an entire length of the transverse bow  10 . The hollow profile seal  11  is formed in one piece from an elastomer body and can be deformed elastically. The hollow profile seal  11  has a water discharge lug  15  which, in the pulled-out covering position of the flat structure  7  ( FIGS. 2 and 5 ), protrudes rearward beyond an upper edge of the rear wall  3 . In the covering position, in which the load bed  2  is closed completely, the hollow profile seal  11  bears sealingly against the rear wall  3  in an elastically deformed manner in the region of a corresponding boundary edge of said rear wall  3 , the water discharge lug  15  which is extended over the entire length of the hollow profile seal  11  being positioned above the upper edge of the rear wall  3  according to  FIG. 5  and partially protruding obliquely rearward beyond the upper side of the upper edge of the rear wall  3 . Accordingly, the hollow profile seal  11  forms a water-tight termination of the flat structure  7  with the rear wall  3  in the closed covering position of the flat structure  7 . 
     Each transverse bow  10 ,  10   a  is provided on its opposite end sides with in each case one sliding body  33  which can be plugged in a non-positive manner via plug-in profiles  34  in the form of plug-in journals into complementary, end-side plug-in profiles of the transverse bow  10 ,  10   a  in the form of plug-in sockets  14 . The sliding body  13  forms an end-side termination of the end side of the respective transverse bow  10 ,  10   a . All the transverse bows  10 ,  10   a  are provided in each case with corresponding sliding bodies  33  on their end sides which lie opposite one another, as can be seen using  FIG. 11 . On an outer side which faces away from the transverse bow  10 ,  10   a , each sliding body  33  has a horizontally extended guide blade (not denoted in greater detail) which is mounted in a guide groove  29  (which will be described in greater detail in the following text) of the respective guide rail arrangement  9  such that it can be moved slidingly along the guide rail arrangement  9 . The guide blade is provided on the edge side with an upwardly protruding retaining cam  35  which ensures positively locking retention of the respective sliding body  33  in the vehicle transverse direction within the guide groove  29  of the guide rail arrangement  9 . 
     Apart from one exception, the sliding bodies  33  of all the transverse bows  10 ,  10   a  are designed identically to one another. This is because the end-side transverse bow  10  which forms an end-side termination of the flat structure  7  is provided with a modified sliding body  33   a . The sliding body  33   a  ( FIG. 10 ) is provided with an additional driver lug M which protrudes downward in a hook-like manner and interacts in a positively locking manner with a corresponding web G of a drive body  32  in a manner which will be described in greater detail in the following text. On its end sides which lie opposite one another, the end-side transverse bow  10  has in each case one sliding body  33   a  of this type which is provided with a corresponding driver lug M. 
     In each case one drive body  32  is mounted longitudinally displaceably in each of the two guide rail arrangements  9 , which drive body  32  is provided in each case with a corresponding web G which enters into a plug-in connection with the corresponding driver lug M in the pull-out direction of the flat structure  7 . To this end, the hook-shaped driver lug M of each sliding body  33   a  is open to the rear toward the cassette housing  8 , with the result that the corresponding web G can dip into the open side of the driver lug M, in order for it to be possible to drive the driver lug M and therefore the sliding body  33   a  in the pull-out direction in a positively locking manner. The plug-in connection which is produced as a result between the corresponding web G and the driver lug M has a force flow of such a magnitude that the plug-in connection between the sliding body  33   a  and the drive body  32  is not released even in the case of a movement in the opposite direction of the drive body  32  in the winding-up direction of the flat structure  7 . 
     The two drive bodies  32  are mounted in each case in a drive channel  27  of the respective guide rail arrangement  9  such that they can be moved glidingly along the respective guide rail arrangement  9 . As can be gathered from  FIG. 8 , the drive channel  27  is open toward the center of the load bed  2 , that is to say toward the flat structure  7 , which otherwise also applies to the guide groove  29 . The drive channel  27  is adjoined laterally to the outside in the guide rail arrangement  9  by a receiving region  30  which serves to receive a drive transmission means which is configured as a cable pull  19 ,  36 ,  18 ,  20  ( FIGS. 6 and 10 ) in the embodiment according to  FIGS. 1 to 18 . Both guide rail arrangements  9  are identical, but are designed so as to be mirror-symmetrical with respect to one another. In each case one cable pull is integrated into both receiving regions  30  of the guide rail arrangements  9  which lie opposite one another. Each cable pull is formed by a wire cable  19  which is deflected over a rear-side deflection roller  36  ( FIG. 10 ) and a cassette housing-side deflection roller  20  and is held on a cable drum  18  which is coaxial with respect to the winding shaft  16 . In this way, one end of the wire cable  19  is held on the cassette housing-side cable drum  18 , whereas an opposite cable end of the wire cable  19  is connected fixedly to the respective drive body  32 . 
     The respective deflection roller  36  is mounted in a stationary manner in the respective guide rail arrangement  9  such that it can be rotated. The receiving region  30 , the drive channel  27  and the guide groove  29  extend continuously with a constant cross section over the entire length of the guide rail arrangement  9 . 
     As can be gathered from  FIGS. 9, 13 and 14 , the flat structure  7  is additionally provided on its longitudinal sides which lie opposite one another with a multiplicity of lateral guide elements  17  which are designed as bead parts and are connected fixedly to the longitudinal edges of the flat structure  7 . Here, the lateral guide elements  17  of in each case one longitudinal side of the flat structure  7  are positioned in a row behind one another in the pull-out direction. The lateral guide elements  17  protrude through the thickness of the flat structure  7  and protrude both to the upper side and to the underside of the respective longitudinal edge of the flat structure  7 . The thickness (as viewed in the vehicle vertical direction) of the lateral guide elements  17  is accordingly substantially greater than a thickness of the flat structure  7 . The lateral guide elements  17  are guided in a positively locking manner in the vehicle transverse direction in the region of each longitudinal side of the flat structure  7  in each case one lateral guide channel  28  of the respective guide rail arrangement  9 . Here, the longitudinal edges of the flat structure  7  protrude in each case transversely with respect to the pull-out direction through a corresponding longitudinal slot into the respective lateral guide channel  28  of the guide rail arrangement  9 . Accordingly, the flat structure  7  is guided over its entire length with its lateral longitudinal edges which lie opposite one another in the guide rail arrangements  9  which lie opposite one another. 
     Each guide rail arrangement  9  is formed by a two-piece hollow profile made from lightweight metal alloy, preferably an aluminum extruded profile, or from a suitable plastic material. The hollow profile comprises a lower structure section  25  and an upper covering section  26  which are detached from one another or can be connected to one another along an approximately horizontal dividing plane. Both the structure section  25  and the covering section  26  are configured in each case as single-piece hollow profile bodies. The structure section  25  comprises the drive channel  27  and the receiving region  30  and a lower half of the lateral guiding channel  28 . The covering section  26  comprises the guide channel  29  for the sliding bodies  33 ,  33   a  of the transverse bows  10 ,  10   a . The covering section  26  is connected to one another via hook-in webs which are complementary with respect to one another and are not denoted in greater detail in the region of that outer side of the guide rail arrangement  9  which faces the side walls  4  and via central, vertically upward or downward protruding supporting webs which are likewise not denoted in greater detail. In the region of the vertical supporting webs, the joining together of the covering section  26  and the structure section  25  is assisted via a plurality of spring clamping elements  31  which serve as connecting means in the form of relief spring clamps which are bent in an S-shape. Here, the supporting webs which are assigned to the structure section  25  have cutouts  39 , into which the spring clamping elements  31  can be inserted. The supporting webs of the covering section  26  are plugged in a simple manner from the top into the mounted spring clamping elements  31 . Accordingly, the respective covering section  26  can be connected to the associated structure section  25  without tools and can be dismantled again without tools in the same way. In the region of said dividing plane between the respective covering section  26  and the structure section  25 , water discharge paths are provided distributed over the entire length of the hollow profile bodies, which water discharge paths, according to the diagrammatic illustration according to  FIG. 14 , can discharge water W, which strikes the flat structure  7  from above, laterally to the outside through the hollow profile bodies via the respective side wall  4  to the vehicle outer side. The water discharge paths are produced by way of water guide bevels  37  in the region of an upper side of the structure section  25  and by way of complementary water discharge openings  38  in the supporting web of the associated covering section  26 . The water discharge bevels  37  are combined with cutouts (not denoted in greater detail) of the upwardly protruding supporting web of the structure section  25 . The water discharge bevels  37  are lowered slightly obliquely downward from the middle of the upper side of the structure section  25  toward the outer side. 
     As can be seen using  FIGS. 15 and 16 , an outer-side side edge of the structure section  25  is also interrupted by corresponding openings in the region of the water discharge bevels  37 , with the result that unimpeded discharging of water through said openings laterally to the outside is made possible. 
     As can be seen using  FIGS. 6 and 7 , the flat structure  7  is wound onto the winding shaft  16  and is unwound from the latter. Here, in the winding-up region in the region of the cassette housing  8 , the transverse bows  10 ,  10   a  are oriented with respect to the winding shaft  16  in such a way that the convex curvature of the transverse bows  10 ,  10   a  protrudes radially to the outside relative to a rotational axis of the winding shaft  16 . Compact winding up of the flat structure  7  together with the transverse bows  10  is ensured as a result. In addition, the transverse bows  10 ,  10   a  are spaced apart from one another, as viewed in the pull-out direction of the flat structure  7 , in such a way that, during winding up of the flat structure  7 , the transverse bows  10  ( FIG. 7 ) in the different winding layers are positioned in each case in a staggered manner with respect to one another. This means that in each case one transverse bow  10  of the respectively outer winding layer is positioned between two transverse bows  10  which are spaced apart from one another of a winding layer which lies radially further to the inside. This likewise ensures compact winding of the flat structure  7  onto the winding shaft  16 . 
     In order to ensure that the transverse bows  10 ,  10   a  are wound onto the winding shaft  16  in a correct, space-saving orientation, deflection means  21 ,  21 ′,  22 ′ are provided which, according to  FIG. 6 , cause S-bend guidance of the flat structure  7  after exiting from the guide rail arrangement  9  and before being wound onto the winding shaft  16 . The deflection means  21 ,  21 ′,  22 ′ are positioned in a stationary manner in the cassette housing  8 . In addition, the deflection means  22 ′ comprises a cleaning strip  22  which cleans an upper side of the flat structure  7 . To this end, the cleaning strip  22  has brushes or other mechanical cleaning elements in the region of its surface which interact mechanically with that surface of the flat structure  7  which slides past in the region of the deflection means  22 ′ and achieve a mechanical cleaning function as a result. 
     Each wire cable  19  is held such that it can be wound up and unwound in each case on a cable drum  18  which is positioned coaxially with respect to the winding shaft  16  on opposite ends of the winding shaft  16 . 
       FIGS. 17 and 18  show merely one cable drum  18  on a front end region of the winding shaft  16 . The cable drum which lies opposite is arranged in the same way and is in an operative connection with the winding shaft like the cable drum  18  which is shown using  FIGS. 17 and 18 . The cable drum  18  is mounted rotatably on an end  41  of the cassette housing  8 . To this end, the end  41  has a rotary bearing ring (not denoted in greater detail), onto which the cable drum  18  is plugged. In addition, a stator part of a tubular motor  40  is fastened to the end  41 , which tubular motor  40  protrudes coaxially into the winding shaft  16  which is designed as a rotationally symmetrical hollow profile. The stator part of the tubular motor  40  is connected fixedly on the end side to the end  41  of the cassette housing  8  via fastening means  42 . In addition, the tubular motor  40  has a rotor part which is mounted in the stator part such that it can be rotated coaxially with respect to the rotational axis of the winding shaft and has a torque transmission section  43  which protrudes axially to the outside beyond the stator part and is connected in a rotationally locking manner to a motor housing  45 . The rotationally locking connection of the torque transmission section  43  of the rotor part of the tubular motor  40  to the motor housing  45  takes place via a polygonal hollow profile section  44  of the motor housing  45 , which hollow profile section  44  is adapted to the torque transmission section  43 . The motor housing  45  is of two-shell construction, in order for it to be possible to achieve simple mounting and dismantling relative to the stator part and to the torque transmission section  43  of the tubular motor  40 . Accordingly, the motor housing  45  is mounted rotatably relative to the stator part of the tubular motor  40 . On its outer shell, the motor housing  45  is provided with integrally formed bearing rings which support the winding shaft  16  radially on the inside. In addition, the motor housing  45  has a cylindrical plug-in section which further assists a non-positive connection of an inner shell of the winding shaft  16  to the motor housing  45 . Accordingly, the winding shaft  16  is connected in a rotationally locking manner to the motor housing  45 . 
     A supporting tube  46  is pushed onto the tubular motor  40  on a front end region of the tubular motor  40 , which front end region faces the end  41 , on which supporting tube  46  a differential coil spring  47  in the form of a helical spring is arranged coaxially. The differential coil spring  47  is connected with one spring end to the motor housing  45  in a rotationally locking manner. The motor housing  45  surrounds the differential coil spring  45  coaxially on the outer side, whereas inner-side support takes place by way of the supporting tube  46 . An opposite spring end of the differential coil spring  47  is connected to the cable drum  48  in a rotationally locking manner. 
     The cable drum  18  (not shown) which lies opposite on the end side is in an operative connection in the same way via a differential coil spring with the winding shaft  16 , with the result that different rotational speeds between the cable drums  18  and the winding shaft  16  and, at the same time, stressing or relieving of the respective differential coil spring  47  can be achieved. Accordingly, the differential coil springs  47  make it possible to compensate for different circumferential speeds between the respective outer-side winding layers of the flat structure  7  depending firstly on the winding or unwinding state and secondly on the rotational movement of the cable drums. The motor housing  45  and the winding shaft  16  are connected to one another merely in a non-positive manner in the circumferential direction, with the result that slipping between the winding shaft  16  and the motor housing  45  is also made possible as soon as excessively high loads occur on the winding shaft  16 . The tubular motor  40  is an electric motor and is supplied with electrical power via current and control lines which are not denoted in greater detail, and is controlled in a suitable way via an electric or electronic control unit. The tubular motor  40  can be rotated in both rotational directions, with the result that the winding shaft  16  can be loaded by the tubular motor  40  both in the winding direction and in the unwinding direction.