Abstract:
A vehicle roof having a roof structure with a roof opening, which, by a roof opening mechanism, can be closed or at least partially uncovered as desired, said roof opening mechanism being designed as an interchangeable insert. Additionally, a roof opening mechanism is proposed, being designed as an interchangeable insert, for unlockable fixation at a roof structure of a vehicle roof, and comprising a frame, which can be placed upon an edge region of the roof structure, said edge region limiting a roof opening.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. application Ser. No. 14/642,976, filed Mar. 10, 2015, the content of which is hereby incorporated herein by reference in its entirety for all purposes. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates to a vehicle roof having a roof structure with a roof opening, and in particular a vehicle roof structure having a roof opening mechanism configured as an interchangeable insert, which can be closed or at least partially uncovered as desired. 
       BACKGROUND 
       [0003]    Motor vehicles having vehicle roofs of the above-described type are known from practice and are for example designed as an off-road vehicle or SUV (Sports Utility Vehicle). The vehicle roof, which is usually a fixed-roof, includes a roof opening above a driver&#39;s seat and a front passenger seat, which roof opening can be closed or at least partially uncovered by a sliding roof arrangement. The sliding roof arrangement is integrated into the roof structure in a permanent fashion and has drive kinematics, which are guided in guide rails being arranged on both sides of the roof opening. The drive kinematics usually have a complex heavy structure, which is reflected in the overall costs of the vehicle roof and of the relevant motor vehicle. 
       SUMMARY 
       [0004]    Vehicle roofs are described whose roof opening can be used as desired by the user. 
         [0005]    Therefore, a vehicle roof is proposed having a roof structure with a roof opening having a roof opening mechanism which can be closed or at least partially uncovered as desired, said roof opening mechanism being designed as an interchangeable insert. wherein the interchangeable insert comprises a base frame, which follows an edge of the roof opening, wherein the roof opening mechanism further comprises a fabric covering element, which, by at least one tensioning bow pivotable with respect to the base frame, is displaceable between a closed position for covering the roof opening and an uncovering position for uncovering the roof opening. 
         [0006]    According to one approach, the roof opening mechanism in the proposed vehicle roof can be installed or removed by a user of the relevant vehicle if required or desired. Manipulation of the roof structure itself, onto which the interchangeable insert can be placed, is not required hereunto. Instead, the proposed vehicle roof can be a variable system in which the roof opening can either be provided with a roof opening mechanism or, alternatively, with a rigid element, or in which the roof opening can also be left completely open. A rigid roof element, which is designed in one piece or in several pieces, can be fixed to the roof structure via the same links as the roof opening mechanism being designed as an interchangeable insert. 
         [0007]    The interchangeable insert is provided with a base frame, which follows an edge of the roof opening. The base frame constitutes the element of the interchangeable insert that serves for linking the roof opening mechanism to the roof structure. This means that the base frame forms a link between the roof opening mechanism and the roof structure or vehicle structure. In principle, the base frame can be realized as a closed frame preferably having four legs or also as an open frame, for example having three legs, e.g., it can have a roughly “U”-shaped layout. 
         [0008]    In order to make it as easy as possible for users of the relevant vehicle to install the roof opening mechanism at the roof structure or to remove the roof opening mechanism from the roof structure, the base frame is preferably attached to the roof structure via fixation elements being manually unlockable. For example, the manually unlockable fixation elements are handle screws, which reach through the roof structure from below. Preferably, in the region of lateral roof beams, two handle screws in each instance reach through the roof structure from below, in order to reach into corresponding screw threads of the base frame from below, said base frame being arranged on the roof structure. 
         [0009]    The roof opening mechanism comprises a fabric covering element, which, by at least one tensioning bow pivotable with respect to the base frame, is displaceable between a closed position for covering the roof opening and an uncovering position for uncovering the roof opening. This means that the tensioning bow constitutes the control element of the roof opening mechanism that is then designed in the manner of a folding roof. The position of the tensioning bow prescribes the position and the tensioning state of the fabric covering element. 
         [0010]    The tensioning bow is in particular mounted at the base frame of the interchangeable insert, to be more precise, in relation to a longitudinal center plane of the roof, it is preferably on each of its two sides mounted via a tensioning bow portion being articulated to a corresponding leg of the base frame. 
         [0011]    In order to be able to secure the fabric covering element in its closed position, in a special embodiment, the tensioning bow, in the closed position, is adjacent to a front edge of the roof opening in order to be secured at the roof structure by a closing mechanism. The roof structure also comprises a front apron of the relevant vehicle, which forms an upper frame leg of a windshield frame of the relevant motor vehicle. 
         [0012]    In order to be able to fold the fabric covering element in a controlled fashion in the uncovering position, the tensioning bow, in a special embodiment, is coupled to a pivotable auxiliary tensioning bow. The auxiliary tensioning bow can be fixed to the fabric covering element or can also only loosely abut on the fabric covering element from below, or it can also reach into a pocket of the fabric covering element. 
         [0013]    In order to be able to move the tensioning bow and the auxiliary tensioning bow when they are coupled, the tensioning bow, in a preferred embodiment, in relation to a vertical longitudinal center plane of the roof, is on each of its two sides connected to the auxiliary tensioning bow via a coupling rod. 
         [0014]    In accordance with a further aspect of the present disclosure, a roof opening mechanism is proposed, being designed as an interchangeable insert, for unlockable fixation at a roof structure of a vehicle roof, and comprising a frame, which can be placed onto an edge region of the roof structure, said edge region limiting a roof opening. The roof opening mechanism can present the features that have previously been described in conjunction with the vehicle roof. 
         [0015]    The frame of the roof opening mechanism can be designed so as to be closed or it can also have only three legs, via which it can be linked to the roof structure, i.e. it can have a U-shaped layout in the broadest sense. 
         [0016]    According to a further aspect of the present disclosure, a vehicle roof is proposed, comprising a roof structure having a roof opening, which, as desired, can be provided with a roof opening mechanism, which is designed as an interchangeable insert of the previously described type, or with a rigid roof element being designed in one part or in several parts. 
         [0017]    Further advantages and advantageous configurations of the subject-matter of the invention can be taken from the description, from the drawing and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0018]    In the drawing, a motor vehicle having a vehicle roof, including a roof opening, is illustrated in a schematically simplified fashion and will be explained in more detail in the following description. 
           [0019]      FIG. 1  shows a perspective view of a vehicle structure having a roof opening, which is closed by a rigid element. 
           [0020]      FIG. 2  shows a view that is similar to  FIG. 1 , but with a roof opening mechanism in the closed position thereof. 
           [0021]      FIG. 3  shows a view that is similar to  FIG. 2 , but in an intermediate position of the roof opening mechanism. 
           [0022]      FIG. 4  equally shows a view that is similar to  FIG. 2 , but in an open position of the roof opening mechanism. 
           [0023]      FIG. 5  shows a side view of the vehicle structure with the roof opening mechanism in the closed position thereof. 
           [0024]      FIG. 6  shows a view that is similar to  FIG. 5 , but in the intermediate position of the roof opening mechanism. 
           [0025]      FIG. 7  shows a view that is similar to  FIG. 5 , but in the open position of the roof opening mechanism. 
           [0026]      FIG. 8  shows the rigid element according to  FIG. 1  on its own. 
           [0027]      FIG. 9  shows a perspective top view onto the roof opening mechanism on its own, in the closed position thereof. 
           [0028]      FIG. 10  shows a view of the roof opening mechanism that is similar to  FIG. 9 , but in the intermediate position. 
           [0029]      FIG. 11  equally shows a view of the roof opening mechanism that is similar to  FIG. 9 , but in the open position. 
           [0030]      FIG. 12  shows a side view of the roof opening mechanism in the closed position thereof. 
           [0031]      FIG. 13  shows a view of the roof opening mechanism that is similar to  FIG. 12 , but in the intermediate position. 
           [0032]      FIG. 14  shows a view of the roof opening mechanism that is similar to  FIG. 13 , but in the open position. 
           [0033]      FIG. 15  shows an inside view of the vehicle structure according to  FIG. 2 , in the closed position of the roof opening mechanism. 
           [0034]      FIG. 16  shows a perspective view of a frame of the roof opening mechanism together with fixation elements. 
           [0035]      FIG. 17  shows a sectional illustration through a lateral beam of the vehicle structure according to  FIG. 2 , with the roof opening mechanism being installed in the region of a fixation element. 
           [0036]      FIG. 18  shows a sectional illustration through a rear frame leg of the roof opening mechanism in the state in which it is installed on the vehicle structure. 
           [0037]      FIG. 19  shows a perspective top view of an alternative embodiment in the closed position, but without illustrating an outer shell. 
           [0038]      FIG. 20  shows a perspective illustration of a headlining of the roof opening mechanism according to  FIG. 19 . 
           [0039]      FIG. 21  shows a top view of the headlining and a main tensioning bow. 
           [0040]      FIG. 22  shows how the headlining is linked to a base frame of the roof opening mechanism. 
           [0041]      FIG. 23  shows a perspective view of the main tensioning bow on its own. 
           [0042]      FIG. 24  shows an exploded illustration of the main tensioning bow. 
           [0043]      FIG. 25  shows a bottom view of the main tensioning bow. 
           [0044]      FIG. 26  shows a first section through the roof opening mechanism in the area of the main tensioning bow. 
           [0045]      FIG. 27  shows a second section through the roof opening mechanism in the area of the main tensioning bow. 
           [0046]      FIG. 28  shows a side view of the roof opening position in the open position and a folding of a fabric covering element. 
           [0047]      FIG. 29  shows a perspective view of a base frame of the roof opening system on its own. 
           [0048]      FIG. 30  shows a perspective illustration of how the main tensioning bow and an auxiliary tensioning bow are linked to the base frame. 
           [0049]      FIG. 31  shows a detail illustration of the main tensioning bow and of the auxiliary tensioning bow and their stops in the closed position of the roof opening mechanism. 
           [0050]      FIG. 32  shows a detail illustration of the main tensioning bow and of the auxiliary tensioning bow and their stops in the open position of the roof opening mechanism. 
           [0051]      FIG. 33  shows a detail top view of the base frame in the area where it is linked to the main auxiliary bow. 
           [0052]      FIG. 34  shows a special embodiment of a linkage of the main tensioning bow. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0053]    In  FIGS. 1 to 18 , a vehicle structure  10  is illustrated, which is part of a passenger car being designed as an all-terrain vehicle and which includes a vehicle roof  12 , which is provided with a roof opening  14 , said roof opening being designed above a driver&#39;s seat and a front passenger seat. The roof opening  14 , with its front edge, is adjacent to a front apron  16 , which forms an upper frame leg of a windshield frame, said upper frame leg extending in the transverse direction of the vehicle. In the rear, the roof opening  14  is adjacent to a fixed-roof portion  18 , which extends up to a rear roof edge  20 . In relation to a vertical longitudinal center plane of the roof, the roof opening  14  is laterally in each instance limited by a tube-like longitudinal roof beam  22 , which can be part of a rollover protection mechanism of the vehicle structure  10  and which is to be considered to be part of the roof structure here. The longitudinal roof beam  22  that is arranged on the left in relation to the forward direction of travel can be taken from  FIG. 17  that is a sectional illustration. In  FIGS. 1 to 7 , rear elongations of the two longitudinal roof beams  22  are illustrated, which extend diagonally downwards into a rear loading space  24  of the vehicle structure  10 . 
         [0054]    In accordance with  FIG. 1 , the roof opening  14  is closed by a rigid roof element  26 , which reaches up to the front apron  16  in the front and up to the fixed-roof portion  18  in the rear. In the edge regions being arranged on the side in relation to the vertical longitudinal center plane of the roof, the rigid roof element  26  covers the two longitudinal roof beams  22 . Laterally, the rigid roof element  26 , on each of its two sides, forms an upper limitation of a door cut-out  48  for a side door  50  of the vehicle structure  12 . 
         [0055]    The rigid roof element  26  is secured in its installed position being illustrated in  FIG. 1  by handle screws, two of which in each instance reach through the longitudinal roof beams  22  from below and two of which reach through the rear fixed-roof portion  18  from below, said handle screws reaching into a corresponding screw thread of the rigid roof element  26  from below. In addition, the rigid roof element  26  is fixed to the front apron  16  by suitable closing lugs. 
         [0056]    As it can be taken from  FIGS. 2 to 7 , the roof opening  14  can, as an alternative to the rigid roof element  26 , be provided with a roof opening mechanism  28 , being designed as an interchangeable insert, which, as it can be taken from  FIGS. 16 to 18 , can be fixed to the roof structure by several handle screws  30 . The handle screws  30  are manually unlockable fixation elements, which reach through the roof structure from below and reach into corresponding screw threads of the roof opening mechanism  28  from below. The handle screws  30  correspond to the handle screws by which the rigid roof element  26  is secured in its installed position. 
         [0057]    As it can in particular be taken from  FIGS. 9 to 14 , the roof opening mechanism  28  being designed as an interchangeable insert includes a base frame  32 , which has an at least nearly U-shaped layout and which consists of two longitudinal legs  34  extending in the longitudinal direction of the vehicle and of a transverse leg  36  connecting the two longitudinal legs  34  to each other at their rear ends. The longitudinal legs  34  have one free face side in the front, respectively, which face side is adjacent to the front apron  16  of the roof structure or vehicle structure  10  in the installed position being illustrated in  FIGS. 2 to 7 . Additionally, the longitudinal legs  34  in each instance are positioned on one of the longitudinal roof beams  22 . The roof opening mechanism  28  is fixed to the roof structure via the base frame  32 . This means that the base frame forms a link to the roof structure. 
         [0058]    As it can be taken from  FIGS. 16 to 18 , two of the handle screws  30  previously having been mentioned also with respect to the rigid roof element  26 , for fixing the roof opening mechanism to the roof structure, reach through one longitudinal roof beam  22 , respectively, from below in order to then reach into a corresponding screw thread  38  from below, which screw thread is designed at the relevant longitudinal leg  34  of the base frame  32 . Additionally, between the longitudinal roof beams  22  of the roof structure or vehicle structure  10  and the respective longitudinal leg of the base frame  32 , in the region of the handle screws  30 , one spacer  56 , respectively, is arranged, the respective handle screw  30  equally reaching through said spacer. 
         [0059]    Two further handle screws  30  reach through a transverse roof beam  40  from below, in order to then reach into a corresponding screw thread  42  from below, which screw thread is designed at the transverse leg  36  of the frame  32 . Here, the transverse leg  36  rests on a seal  44 , which is designed at the front edge of the fixed-roof portion  18 . The handles of the handle screws  30  being accessible from the vehicle interior in the installed position can laterally be encircled by an interior paneling  46  of the roof structure. Alternatively, the base frame  32  might be fixed to the front apron and to B-pillars of the vehicle structure. Then, no longitudinal roof beams are required for fixing the base frame. 
         [0060]    The longitudinal legs  34  of the base frame  32 , which rest on the longitudinal roof beams  22 , form one upper limitation, respectively, of the door cut-out  48 , which can be closed by the respective side door  50  of the vehicle structure  10 . The side door  50  has an upper frame piece  52 , at which a seal  54  is arranged, which, in the closed position of the door  50 , interacts with a corresponding sealing surface at the bottom side of the respective longitudinal leg  34  of the base frame  32 . 
         [0061]    The roof opening mechanism  28  comprises a main tensioning bow  58 , which is designed so as to be substantially U-shaped and which is articulated to the longitudinal legs  34  of the base frame  32  by its free legs  60  via hinge points  62 . The free legs  60  of the main tensioning bow  58 , at their ends facing away from the hinge points  62 , are connected to each other via a transverse leg, which, in the closed position being illustrated in  FIGS. 2, 5 and 9 , forms a front edge of the roof opening mechanism  28 , said edge being adjacent to the front apron  16  of the vehicle structure  10 . The transverse leg  64  constitutes a front bow of the roof opening mechanism  28 . 
         [0062]    The two free legs  60  of the main tensioning bow  58  are in each instance connected to a coupling link  68  via a hinge point  66 , said coupling link being articulated to a U-shaped auxiliary tensioning bow  70  via a hinge point  69 . The auxiliary tensioning bow  70 , on each of its two sides, includes a leg  72 , which is articulated in the rear end region of the respective longitudinal leg  34  of the base frame  32  via a hinge point  74 . The two legs  72 , at their ends facing away from the hinge points  74 , are connected to each other via a transverse leg  76  constituting an intermediate bow. 
         [0063]    The tensioning bow arrangement being formed by the main tensioning bow  58 , the auxiliary tensioning bow  70  and the coupling links  68  serves for spanning a fabric covering element  78 , which, in the closed position being illustrated in  FIGS. 2, 5, 9, 12 and 15 , spans the roof opening  14  and which, in its uncovering and open position being illustrated in  FIGS. 4, 7, 11 and 14 , uncovers the roof opening  14  in the region being encircled by the base frame  32 . In the closed position, the main tensioning bow  58  is fixed to the front apron  16  by two closing lugs  84 . 
         [0064]    The fabric covering element  78 , with its edge being arranged in the front in the longitudinal direction of the vehicle, is linked to the transverse leg  64  of the main tensioning bow  58  and is attached to the transverse leg  36  of the base frame  32  with its rear edge. As it can be taken from  FIG. 17 , the fabric covering element  78 , in its closed position, abuts on a flange  80  of the respective longitudinal leg  34  of the base frame  32  with its edges being arranged on the side in relation to the vertical longitudinal center plane of the roof. Hereunto, at the inner side of the fabric covering element  78 , a sealing layer  82  made of an elastomer material or a textile member is in each instance applied, which sealing layer abuts on the outer side of the flange  80 . 
         [0065]      FIGS. 19 to 33  illustrate a second embodiment of a roof opening mechanism  28 ′, which is also designed as an interchangeable insert and can be fixed to a roof structure of a vehicle by means of multiple handle screws in correspondence to the embodiment according to  FIGS. 1 to 18 . 
         [0066]    The roof opening mechanism  28 ′ designed as an interchangeable insert has a base frame  32 , which is shown on its own in  FIG. 29  and which is U-shaped in the top view. Thus, the base frame  32  has two longitudinal legs  34  extending in the longitudinal direction of the vehicle and a transverse leg  36  connecting the two longitudinal legs  34  at their rear ends. Each of the longitudinal legs  34  has a free face side in the front, which face side is adjacent to a front apron of the relevant roof structure in the installed position. The roof opening mechanism  28 ′ is fixed to the vehicle structure via the base frame  32 . Regarding the installed position, it is referred to the above description of the embodiment of  FIGS. 1 to 18 . 
         [0067]    The base frame  32  is designed in one piece and is made of plastic, a composite material, a sheet mold compound structure, an organic sheet structure and/or a honeycomb structure. The base frame  32  can be manufactured using an injection-molding method or another type of molding method for processing a plastic material. For the purpose of stiffening, the base frame  32  has a ribbing, which can be designed as a crosswise ribbing or the like. 
         [0068]    The base frame  32  can be provided with a graining or the like, which is produced during the manufacturing process. Thus, painting the base frame  32  is unnecessary. 
         [0069]    In relation to a vertical longitudinal center plane of the roof, mounting sockets  100  and  102  are integrally formed on each of the two sides of the base frame  32 , which mounting sockets consist of two vertical lugs, which are provided with a hole for receiving a mounting bolt. The mounting sockets  100  formed on the two longitudinal legs  34  serve to mount a main tensioning bow  58  in a pivoting manner, whereas the mounting sockets  102  serve to mount an auxiliary tensioning bow  70  in a pivoting manner. By means of the main tensioning bow  58  and the auxiliary tensioning bow  70 , on the one hand, a fabric covering element  78  forming an outer shell and, on the other hand, a headlining  104  can be adjusted between a closed position ( FIG. 19 ) covering the relevant roof opening and an open position ( FIG. 28 ) uncovering the roof opening in correspondence to the embodiment according to  FIGS. 1 to 18 . Additionally, a foldable insulation (not illustrated) can be arranged between the headlining  104  and the fabric covering element  78  being an outer shell. 
         [0070]    The main tensioning bow  58  comprises a transverse leg  64  extending in the transverse direction of the roof and being a front header, which, at each of its ends arranged on both sides, is connected to a linkage  106 , which is realized as a lever and is pivotably mounted on the relevant mounting socket  100  of the base frame  32 . The transverse leg  64  of the main tensioning bow  58  has a two-shell structure and comprises a trough-shaped lower shell  108 , which is designed as an injection-molded part and has a ribbing for the purpose of stiffening. The lower shell  108  can also comprise a honeycomb structure with a paper honeycomb. As a second shell, the transverse leg  64  of the main tensioning bow  58  comprises an upper shell  110 , which is formed from a steel sheet or an aluminum sheet and is screwed to the lower shell  108  by means of mushroom screws  112  or by means of clips. The linkages  106  are attached to the upper shell  110 . At its rear edge, the upper shell  110  has hook-like lugs  113 , into which the headlining  104  is hooked. For this purpose, the headlining  104  has a front strip  114 , which comprises lugs  116  having recesses that are penetrated by the hook-like lugs  113  of the upper shell  110  of the transverse leg  64 . The strip  114  of the headlining  104  is made of a polypropylene material and sewed to the headlining  104 . Alternatively, it can also be connected to the headlining  104  using a an injection-molding method or in any other way. 
         [0071]    At its rear edge, the headlining  104  has a rear strip  118 , which is provided with hooking lugs  120  hooked into hook-like projections  122 . The hook-like projections  122  are formed integrally on the base frame  32 . In correspondence to the front strip  114 , the rear strip  118  of the headlining  104  is made of a polypropylene material and sewed to the headlining  104 . Alternatively, it can also be connected to the headlining  104  using a an injection-molding method or in any other way. 
         [0072]    As in the embodiment according to  FIGS. 1 to 18 , the linkages  106 , which are manufactured from a straight stamped part, are connected to a coupling link  68  via a hinge point  66 , which coupling link  68  is connected to a linkage  124  of the auxiliary tensioning bow  70 . The hinge point  69  is arranged in a central portion of the respective linkage  124  of the auxiliary tensioning bow  70 . On one side, the linkages  124  of the auxiliary tensioning bow  70  are pivotably mounted on the relevant mounting socket  102  in the area of the respective longitudinal leg  34  of the base frame  32 . On the other side, the linkages  124  are connected to each other via a transverse leg  76  of the auxiliary tensioning bow  70 . 
         [0073]    To achieve defined folding, the headlining  104  is attached to the transverse leg  76  of the auxiliary tensioning bow  70  via a shell-like attachment strip  126 , and the front edge of the fabric covering element  78  is connected to the transverse leg  64  of the main tensioning bow  58 , the rear edge is connected to the transverse leg  36  of the base frame  32  and a middle portion is connected to the transverse leg  76  of the auxiliary tensioning bow  70 . As can be taken from  FIG. 28 , the fabric covering element  78  thus undergoes defined folding when being adjusted from the closed position covering the roof opening into the open position uncovering the roof opening, and it does so in such a manner that it does not protrude beyond the main tensioning bow  58  in the direction of the rear of the relevant vehicle. Instead, it is folded once between the main tensioning bow  58  and the auxiliary tensioning bow  70  and once between the auxiliary tensioning bow  70  and the base frame  32 . 
         [0074]    For being linked to the transverse leg  64  of the main tensioning bow  58  and to the transverse leg  36  of the base frame  32 , the fabric covering element  78  can have a material strip at each of the corresponding edges, which strip is made of a polypropylene material and is formed in correspondence to the strips  114  and  118  of the headlining  104 . 
         [0075]    Furthermore, a closing lug  84  is attached to the transverse leg  64  of the main tensioning bow  58 , via which the main tensioning bow  58  can be fixed to the front apron of the relevant vehicle. The base of the closing lug  84  is screwed to the upper shell  110  of the transverse leg  64 . 
         [0076]    As can be taken in particular from  FIGS. 30 to 33 , the linkages  106  and  124  of the main tensioning bow  58  and of the auxiliary tensioning bow  70  are mounted on the mounting sockets  100  and  102 , respectively, via a hinge pin  130  or alternatively or additionally via bushings and clips. To ensure the distance between the respective linkage  106  of the main tensioning bow  58  and the respective coupling link  68  in the area of the hinge point  69 , a bushing  130  is provided, which is welded to the linkage  106 . A screw  132  reaches into the bushing  130  from the inside, which screw reaches through a corresponding mounting hole of the coupling link  68 . 
         [0077]    Additionally or alternatively, washers, stepped rivets, blind rivets and/or clips can be provided in the area of the sockets  100  and  102  or of the corresponding hinge points and in the area of the hinge points  66  and  69  so as to realize the respective hinge point in the optimal way. 
         [0078]    To define the closed position of the linkage arrangement formed by the main tensioning bow  58 , the auxiliary tensioning bow  70  and the coupling links  68 , end stoppers  134  are arranged on the inner side of the coupling links  68 , i.e. on the side facing toward the longitudinal center plane of the vehicle, which end stoppers  134  are made of a cushioning plastic sleeve and against which the auxiliary tensioning bow  70  rests in the closed position (cf.  FIG. 31 ). To define the open position of the linkage arrangement, the linkages  124  of the auxiliary tensioning bow  70  each have an end stopper  136  on their inner sides in the area between the respective mounting socket  102  and the respective hinge point  69 , which end stopper  136  is also formed by a screwed-on sleeve made of a cushioning material. Thus, the linkage arrangement supports itself in its end positions. 
         [0079]    In an alternative embodiment of the roof opening mechanism of the kind described above, the linkages of the main tensioning bow and/or of the auxiliary tensioning bow can each be formed by a straight tube-like link  138 , which is shown on its own in  FIG. 34 . The tube-like link  138  has a diameter of about 16 mm to 20 mm and exhibits high stiffness. For being articulated to the base frame, the tube-like link  138  can be provided with an inserted plastic end piece  140 , which may be an injection-molded component and can be designed to have a hole to be penetrated by a hinge pin. Alternatively, hinge pins can also be integrated in one piece on the plastic end piece, which hinge pins penetrate the corresponding mounting openings of the base frame. 
         [0080]    Another embodiment of a roof opening mechanism not illustrated, which largely corresponds to the roof opening mechanisms described above, is additionally characterized by a spring-elastic element, which facilitates operating, i.e. adjusting, the roof opening mechanism between the closed position and the open position. In the case at hand, the spring-elastic element is a torsion spring, which is supported at the base frame on the one side and at the main tensioning bow on the other side and applies pretension to the latter in the opening direction. 
         [0081]    Another embodiment not illustrated is provided with a drive motor for operating the linkage arrangement of the roof opening mechanism. Otherwise, this embodiment, too, corresponds to the embodiments described above. The drive motor is an electric motor driving the main tensioning bow. 
         [0000]    
       
         
               
             
               
               
             
           
               
                   
               
               
                 List of reference numerals 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 vehicle structure 
               
               
                 12 
                 vehicle roof 
               
               
                 14 
                 roof opening 
               
               
                 16 
                 apron 
               
               
                 18 
                 fixed-roof portion 
               
               
                 20 
                 rear roof edge 
               
               
                 22 
                 longitudinal roof beam 
               
               
                 24 
                 loading space 
               
               
                 26 
                 rigid element 
               
               
                 28 
                 roof opening mechanism 
               
               
                 30 
                 handle screw 
               
               
                 32 
                 base frame 
               
               
                 34 
                 longitudinal leg 
               
               
                 36 
                 transverse leg 
               
               
                 38 
                 screw thread 
               
               
                 40 
                 transverse roof beam 
               
               
                 42 
                 screw thread 
               
               
                 44 
                 seal 
               
               
                 46 
                 interior paneling 
               
               
                 48 
                 door cut-out 
               
               
                 50 
                 side door 
               
               
                 52 
                 frame piece 
               
               
                 54 
                 seal 
               
               
                 56 
                 spacer 
               
               
                 58 
                 main tensioning bow 
               
               
                 60 
                 free leg 
               
               
                 62 
                 hinge point 
               
               
                 64 
                 transverse leg 
               
               
                 66 
                 hinge point 
               
               
                 68 
                 coupling link 
               
               
                 69 
                 hinge point 
               
               
                 70 
                 auxiliary tensioning bow 
               
               
                 72 
                 free leg 
               
               
                 74 
                 hinge point 
               
               
                 76 
                 transverse leg 
               
               
                 78 
                 fabric covering element 
               
               
                 80 
                 Flange 
               
               
                 82 
                 sealing layer 
               
               
                 84 
                 closing lug 
               
               
                 100 
                 mounting socket 
               
               
                 102 
                 mounting socket 
               
               
                 104 
                 headlining 
               
               
                 106 
                 linkage 
               
               
                 108 
                 lower shell 
               
               
                 110 
                 upper shell 
               
               
                 112 
                 mushroom screws 
               
               
                 113 
                 hook-like lugs 
               
               
                 114 
                 front strip 
               
               
                 116 
                 lug 
               
               
                 118 
                 rear strip 
               
               
                 120 
                 hooking lug 
               
               
                 122 
                 hook-like projection 
               
               
                 124 
                 linkage 
               
               
                 126 
                 locking strip 
               
               
                 130 
                 hinge pin/bushing 
               
               
                 132 
                 screw 
               
               
                 134 
                 end stopper 
               
               
                 136 
                 end stopper 
               
               
                 138 
                 tube-like link 
               
               
                 140 
                 plastic end piece