Patent Publication Number: US-2023151668-A1

Title: Closure device for a charging or tank flap of an automotive vehicle

Description:
BACKGROUND 
     The invention relates to a closure device for a charging or tank flap of an automotive vehicle. 
     From DE 10 2016 110 869 A1, a closure device for a charging or tank flap of an automotive vehicle comprising a flap element and a guide unit disposed within a body of the automotive vehicle is already known. The flap element is traversable between a closed position and an open position along the guide unit by means of a push-pull cable, wherein the guide unit is formed in such a manner that the flap element performs a traversing motion and a lifting motion during the movement between the closed position and the open position. In the open position, the flap element is disposed within the body of the automotive vehicle. 
     It is an object of the present invention to provide a generic closure device for a charging or tank flap of an automotive vehicle with good properties regarding precise and reliable opening and closing of the charging or tank flap. The object is achieved by the features of claim  1 . Examples of the invention are indicated in the dependent claims. 
     DISCLOSURE 
     The invention is based on a closure device for a charging or tank flap of an automotive vehicle, comprising a flap element, comprising a drive unit including an electrical actuator for traversing the flap element between a closed position and an open position and a guide unit disposed within a body of the automotive vehicle, wherein the guide unit includes two guide rails extending in parallel to one another and two carriages arranged to be traversable on the guide rails, on which the flap element is arranged. 
     The drive unit may include at least one gear unit for the synchronous transmission, to both carriages, of a drive movement generated by the actuator. 
     The closure device is provided, in particular, to close a charging connector or a filler pipe by means of a flap element when the automotive vehicle is not being filled up or charged, respectively, and to expose the charging connector or the filler pipe by traversing the flap element from a closed position to an open position to enable a filling operation or a charging operation, respectively. “Provided” should be understood to mean, in particular, especially programmed, configured and/or equipped. That an object is provided for a particular function should be understood to mean, in particular, that the object fulfills and/or performs this particular function in at least one application and/or operating state. The flap element is provided, in particular, to close an opening in the body of the vehicle, behind which the charging connector or the filler pipe, respectively, is arranged, in a largely water- and/or dirt-tight manner, in particular, in the closed position. 
     Traversing of the flap element is performed by means of a drive unit, which is fully disposed within a body of the automotive vehicle. The drive unit comprises a guide unit having two guide rails, which extend within the body of the automotive vehicle. In particular, the guide rails extend essentially parallel to one another. “Essentially parallel” should be understood to mean, in particular, an alignment in a direction relative to a reference direction, in particular in a plane, wherein the direction deviates from the reference direction by less than 2°, particularly less than 1°, and more particularly less than 0.5°. The guide rails define the traversing path of the flap element during opening or closing of the charging or tank flap of the automotive vehicle. Each of the guide rails has a traversing region and a lifting region. During an opening operation, the flap element is traversed away from the body opening along a traversing region of the guide rails and, during a closing operation, the flap element is traversed toward the body opening within the body along the traversing region of the guide rails. During traversal of the flap element along the traversing regions of the guide rails, the flap element performs a traversing motion extending at least essentially parallel to the body of the automotive vehicle. The lifting region of the guide rails is arranged in the region of the body opening to be closed. In the lifting region, the flap element performs a lifting motion at least essentially perpendicular to the traversing motion. The expression “essentially perpendicular” is to define, in particular, an alignment in a direction relative to a reference direction, wherein the direction and the reference direction define an angle of 90°, in particular as viewed in a plane, and the angle has a maximum deviation of, in particular, less than 5°, particularly less than 2° and more particularly less than 1°. During an opening operation, the flap element is at first displaced in a direction almost perpendicular to the access opening by a lowering movement, so that the flap element is offset in parallel toward the interior of the body of the automotive vehicle. The subsequent traversing motion then causes the flap element to be displaced almost in parallel to the body, thus exposing the access opening. Correspondingly, during a closure operation, the flap element is first displaced by the traversing motion in parallel to the body toward the access opening, and subsequently lifted into the access opening by the lifting motion, thus closing the same. 
     The drive unit also includes an electric actuator for the generation of a drive movement for driving the flap element. In addition, the drive unit includes two carriages, each one of which being arranged to be traversable on the guide rails. The flap element is arranged between the guide rails and linked to the carriage via pivotable connecting elements. Due to the connection to the flap element, moving the carriages along the guide rails causes a movement of the flap element. The guide rails have guide grooves in which guide pins of the flap element engage. This causes rail-guiding of the flap element. The guiding pins of the flap element are passed, in particular, through an opening in the connecting elements through the connecting elements into the guide grooves of the guide rails. In particular, the connecting elements are pivotable about the passed-through guiding pins of the flap element. At an end opposite to the passed-through guiding pins of the flap element, the connecting elements are pivotably supported on the carriages. The carriages include, in particular, pivoting axles integrally formed therewith, which protrude, in particular, into corresponding openings of the connecting elements. At the transition from the traversing region to the lifting region of the guide rails, the guide grooves have a change in direction toward the access opening. The change in direction is at least essentially by 90°. The path of the guide grooves in the lifting region is thus at least essentially perpendicular to the path of the guide grooves in the traversing region. During a closing operation, the guiding pins of the flap element follow the guide grooves, wherein the change in direction of the guide grooves causes pivoting of the connecting elements about the pivoting axles of the carriage elements in the direction toward the access opening. Pivoting of the connecting elements, in turn, causes a lifting motion of the flap element connected to the connecting elements toward the access opening. The connecting elements assume a toggle-joint position in the closed position of the flap element, thus achieving self-locking of the flap element. In a corresponding fashion, during an opening operation, the change in direction of the guide grooves causes pivoting of the connecting elements about the pivoting axles of the carriage elements away from the access opening, thus causing a lowering motion of the flap element linked to the connecting elements away from the access opening. 
     To convert the drive movement generated by the actuator into a movement of the flap element, the drive unit has at least one, in particular, one-gear or multi-gear gear unit. The at least one gear unit is arranged, in particular, at one of the guide rails. In particular, the at least one gear unit is directly driven by the actuator. The gear unit does not directly cooperate with the flap element, but transmits the drive motion to the carriages, to which the flap element is linked. The movement of the carriages, in turn, causes movement of the flap element linked to the carriages. In particular, the gear unit is provided to convert a rotatory drive movement of the actuator to a translatory movement of the carriages along the guide rails. The drive movement may be synchronously transmitted to both carriages so that there is a synchronous operation of the carriages. 
     To detect an opening request, strain gauges can be provided which can be arranged, in particular, at at least one of the guide rails. Pressing on the covering element will lead, in particular, to deformation of the guide rails, which can be detected by the strain gauges. This can be used to detect an opening request, and the actuator can be controlled accordingly. To traverse the covering element even in a deenergized state of the actuator from a closed position to an open position, an emergency unlocking device is provided. To operate the emergency unlocking device, the latter includes an emergency unlocking pull. Pulling on the emergency unlocking pull results in a further element connected to the emergency unlocking pull of the emergency unlocking device to act on at least one of the carriages in such a manner that it is displaced along the guide rail by a certain distance. This moves the connecting elements out of the toggle-joint position and releases the self-locking of the flap element so that the flap element can be manually further moved and the charging or tank flap can be opened even when the actuator is not energized. 
     Such an example enables a generic closure device for a charging or tank flap of an automotive vehicle to be provided with regard to a precise and reliable opening and closing of the charging or tank flap of the automotive vehicle. In particular by using at least one gear unit for driving the carriages to which the flap element is linked, precise and reliable traversal of the flap element and thus precise and reliable opening and closing of the charging or tank flap can be achieved. 
     Moreover, for each of the carriages to have a rack, each of the racks may be provided with a pinion gear directly or indirectly driven by the actuator, and provided to convert a rotatory movement of each of the gears to a movement of each of the carriages along one of the guide rails. The racks may be integrally formed with the carriage elements. The racks extend, in particular, over the entire length of the carriages. In particular, a rack of at least one of the carriages meshes with a pinion gear directly or indirectly driven by the actuator in each traversing position of the carriages, or in each traversing position of the flap element connected to the carriages. In particular, the racks of both carriages can mesh with a pinion gear directly or indirectly driven by the actuator in each traversing position of the carriages, or in each traversing position of the flap element connected to the carriages. This enables a rotatory movement generated by the actuator to be converted to a movement of the carriages along the guide rails. 
     In one example, the drive unit may include a cross shaft driven by the at least one gear unit, the cross shaft extending between the two guide rails and being rotatably supported in the guide rails, wherein the cross shaft bears a pinion gear on each of its ends, each meshing with a rack of each carriage. The gears of the cross shaft are fitted on the ends of the cross shaft, in particular, in a torque-resistant manner. In particular, the gears are integrally formed with the cross shaft. One gear of the cross shaft meshes, in particular, with a gear of the gear unit. The rotatory movement generated by the actuator is transmitted to the cross shaft via the gear unit thus causing a rotatory movement of the cross shaft. The gears of the cross shaft transmit the rotatory movement of the cross shaft to the racks of the carriages, and thus the carriages are moved along the guide rails. The cross shaft is supported, in particular, in the guide rails by means of plain bearings. This allows easy synchronous driving and thus a synchronous operation of the carriages to be achieved 
     In an example, the drive unit may include two gear units, each arranged on one of the guide rails and provided to synchronously transmit a drive movement of the actuator to both carriages. The two gear units are arranged opposite one another at the guide rails. The two gear units are identically formed in particular as regards their gear ratio. In particular, only one of the gear units is directly driven by the actuator. The two gear units are coupled to one another from a drive point of view so that a drive movement from the gear unit directly driven by the actuator is transmitted to the other gear unit. Each of the gear units may directly drive at least one gear, each of the pinion gears meshing with a rack of a carriage. By using two gear units, each driving one of the carriages, easy synchronous driving of the two carriages can be achieved. 
     It is also provided that the drive unit includes a cross shaft driven by a first one of the gear units, the cross shaft transmitting a rotatory movement of a gear of the first gear unit to an input gear of the second gear unit. By these means, a synchronous operation of the gear units and thus a synchronous operation of the carriages driven by means of the gear units can be achieved. The cross shaft driven by the first gear unit may comprise a pinion gear on the actuator side which meshes with the rack of the actuator-side carriage as a function of a traversing position of the actuator-side carriage. In particular, the actuator-side gear of the cross shaft is provided to carry out driving of the carriage when the latter is traversed out of the engagement region of a first gear driving the carriage directly driven by the gear unit. This allows a carriage to be traversed along a guide rail over a large traversing distance. 
     Furthermore, it is provided for the drive unit to include a cross shaft extending between the two carriages and whose ends are rotatably supported in the carriages, wherein the cross shaft is driven by moving at least one of the carriages. Preferably, each of the guide rails of the guide unit has one rack, and the cross shaft has a pinion gear at each of its ends, each meshing with a rack of one of the guide rails. By these means, a synchronous operation of the carriages can be achieved. 
     The closure device according to the invention is not limited to the above-described application and examples. In particular, the closure device according to the invention, to fulfill a mode of operation described herein, can include a number of individual elements, components and units deviating from the number mentioned herein. 
    
    
     
       DRAWING 
       Further advantages can be derived from the following description of the drawings. In the drawings, two examples of the invention are shown. The drawings, the description and the claims comprise numerous features in combination. The person skilled in the art will suitably also regard the features in isolation and combine them to further sensible combinations. 
       In the drawings: 
         FIG.  1    shows a perspective view of a closure device for a charging or tank flap; 
         FIG.  2    shows a further perspective view of the closure device; 
         FIG.  3    shows a further perspective view of the closure device without an actuator; 
         FIG.  4    shows a cross shaft of the closure device; 
         FIG.  5    shows a perspective view of the flap element of the closure device; 
         FIG.  6    shows a further perspective view of the flap element of the closure device; 
         FIG.  7    shows a further perspective view of the closure device without flap element; 
         FIG.  8    shows a further perspective view of the closure device without flap element and without carriage; 
         FIG.  9    shows a further perspective view of the closure device without flap element and without carriage; 
         FIG.  10    shows a perspective view of an alternative closure device for a charging or tank flap; 
         FIG.  11    shows a further perspective view of the closure device of  FIG.  10   ; 
         FIG.  12    shows a further perspective view of the closure device of  FIG.  10    without actuator; 
         FIG.  13    shows a further perspective view of the closure device of  FIG.  10    without actuator and without flap element; 
         FIG.  14    shows a further perspective view of the closure device of  FIG.  10    without actuator and without flap element; 
         FIG.  15    shows a perspective view of the flap element of the closure device of  FIG.  10   ; 
         FIG.  16    shows a further perspective view of the flap element of the closure device of  FIG.  10   ; 
         FIG.  17    shows a further perspective view of the closure device of  FIG.  10    without actuator, without flap element, and without carriage; and 
         FIG.  18    shows a further perspective view of the closure device of  FIG.  10    without actuator, without flap element, and without carriage. 
     
    
    
     DESCRIPTION OF THE EXAMPLES 
       FIGS.  1  to  9    show various views, or partial views, of a closure device  10   a  for a charging or tank flap of an automotive vehicle. The closure device  10   a  includes a flap element  12   a  for closing a body opening of the automotive vehicle, behind which the charging connection or a tank connector of the automotive vehicle is situated. To traverse the flap element  12   a  between a closed position and an open position, the closure device  10   a  includes a drive unit  14   a .  FIGS.  1  to  3    show the flap element  12   a  in the closed position. The drive unit  14   a  comprises an electric actuator  16   a  and a guide unit  18   a . In a state of the closure device  10   a  installed in the automotive vehicle, the guide unit  18   a  is entirely accommodated within a body of the automotive vehicle. The guide unit  18   a  includes two guide rails  20   a ,  22   a  extending in parallel to one another. The actuator  16   a  of the drive unit  14   a  is arranged at one guide rail  20   a . The guide rails  20   a ,  22   a  extend within the body of the automotive vehicle, in particular, at least essentially parallel to a contour of the body. Moreover, the guide unit  18   a  comprises two carriages  24   a ,  26   a  which are arranged to be traversable on the guide rails  20   a ,  22   a  and on which the flap element  12   a  is arranged. The flap element  12   a  is arranged between the guide rails  20   a ,  22   a  and is linked to the carriages  24   a ,  26   a  via three pivotable connecting elements  64   a ,  66   a ,  68   a.    
     The drive unit  14   a  includes a gear unit  28   a  in addition to the actuator  16   a . The gear unit  28   a  is provided to synchronously transmit a drive movement generated by the actuator  16   a  to both carriages  24   a ,  26   a . The gear unit  28   a  is arranged at the guide rail  20   a  at which the actuator  16   a  is also arranged. To transform a rotatory movement generated by the actuator  16   a  to a movement of the carriages  24   a ,  26   a , each of the carriages  24   a ,  26   a  has a rack  30   a ,  32   a . Each of the racks  30   a ,  32   a  of the carriages  24   a ,  26   a  meshes with a gear  34   a ,  36   a  driven by the actuator  16   a , in particular via the gear unit  28   a . The racks  30   a ,  32   a  of the carriages  24   a ,  26   a  are provided to convert a rotatory movement of each of the gears  34   a ,  36   a  driven by the actuator  16   a  to a movement of each of the carriages  24   a ;  26   a  along each of the guide rails  20   a ,  22   a.    
     To achieve synchronous operation of the carriages  24   a ,  26   a , the drive unit  14   a  includes a cross shaft  40   a  driven by the gear unit  28   a . The cross shaft  40   a  extends between the two guide rails  20   a ,  22   a . The cross shaft  40   a  is rotatably supported in the guide rails  20   a ,  22   a . The cross shaft  40   a  bears a pinion gear  34   a ,  34   b  at each of its ends, which meshes with a rack  30   a ,  32   a  of a carriage  24   a ,  26   a.    
     During opening or closing of a charging or tank flap, the guide rails  20   a ,  22   a  define the traversing path of the flap element  12   a . Each of the guide rails  20   a ,  22   a  has a traversing region  60   a  and a lifting region  62   a . During traversal of the flap element  12   a  along the traversing regions  60   a  of the guide rails  20   a ,  22   a , the flap element  12   a  performs a traversing movement extending essentially in parallel to the body of the automotive vehicle. In the lifting region  62   a , the flap element  12   a  performs a lifting movement extending essentially perpendicular to the traversing movement. To guide the flap element  12   a  and to generate the traversing movement and the lifting movement of the flap element  12   a , each of the guide rails  20   a ,  22   a  has a guide groove  70   a ,  84   a . Two guiding pins  72   a ,  74   a  of the flap element engage in the guide grooves  70   a ,  84   a . This achieves rail-guiding of the flap element  12   a  along the guide rails  20   a ,  22   a , or along the guide grooves  70   a ,  84   a  of the guide rails  20   a ,  22   a . The guiding pins  72   a ,  74   a  of the flap element  12   a  are passed through openings  76   a  in two connecting elements  64   a ,  66   a  through these two connecting elements  64   a ,  66   a  into the guide grooves  70   a ,  84   a  of the guide rails  20   a ,  22   a . The two connecting elements  64   a ,  66   a  are pivotable about the passed-through guiding pins  72   a ,  74   a  of the flap element  12   a . The third connecting element  68   a  is pivotably arranged at the flap element  12   a  via a pin  80   a  arranged on the third connecting element  68   a  in a torque-resistant manner. The carriages  24   a ,  26   a  comprise pivoting axles  82   a  protruding into corresponding openings  78   a  of the connecting elements  64   a ,  66   a ,  68   a . The connecting elements  64   a ,  66   a ,  68   a  are pivotably arranged on the carriages  24   a ,  26   a  via the pivoting axles  82   a.    
     The guide grooves  70   a ,  84   a  of the guide rails  20   a ,  22   a , in the transition from the traversing region  60   a  to the lifting region  62   a  of the guide rails  20   a ,  22   a , have a change in direction of at least essentially 90°. The path of the guide grooves  70   a ,  84   a  in the lifting region  62   a  is thus at least essentially perpendicular to the path of the guide grooves  70   a ,  84   a  in the traversing region  60   a . During a closing operation, the guiding pins  72   a ,  74   a  of the flap element  12   a  follow the guide grooves  70   a ,  84   a , wherein the change in direction of the guide grooves  70   a ,  84   a  causes pivoting of the connecting elements  86   a ,  66   a ,  68   a  about the pivoting axles  82   a  of the carriage elements  24   a ,  26   a . Pivoting of the connecting elements  64   a ,  66   a ,  68   a , in turn, causes a lifting movement of the flap element  12   a  linked to the connecting elements  64   a ,  66   a ,  68   a . In the closed position of the flap element  12   a , the connecting elements  64   a ,  66   a  assume a toggle-joint position, thus achieving self-locking of the flap element  12   a  in the closed position. 
     During a closing operation, the flap element  12   a , due to the guiding by the guide rails  70   a ,  84   a , is first displaced in parallel to a body of the vehicle toward an access opening by a traversing movement, and is subsequently lifted into the access opening by a lifting movement, thus closing it. During an opening operation, the flap element  12   a  is first displaced in an almost perpendicular direction by a lowering movement opposing the lifting movement so that the flap element  12   a  is offset in parallel toward the interior of the body of the automotive vehicle. The subsequent traversing movement causes the flap element  12   a  to be displaced in a direction almost parallel to the body, thus exposing an access opening. 
       FIGS.  10  to  18    show a further example of the invention. The following description and the drawings are essentially limited to the differences between the examples, wherein, with reference to similarly-designated components, in particular in relation to components having the same reference numerals, reference can basically be made to the drawings and/or the description of the other example. To differentiate between the examples, the letter a has been appended to the reference numerals of the examples of  FIGS.  1  to  9   . In the example of  FIGS.  10  to  18   , letter a has been replaced by letter b. 
       FIGS.  10  to  18    show various views or partial views of an alternatively formed closure device  10   b  for a charging or tank flap of an automotive vehicle. The closure device  10   b  includes a flap element  12   b  for closing a body opening of the automotive vehicle, behind which a charging connector or a filler pipe of the automotive vehicle is arranged. To traverse the flap element  12   b  between a closed position and an open position the closure device  10   b  has a drive unit  14   b . In  FIGS.  10  to  12    the flap element  12   b  is shown in the closed position. The drive unit  14   b  comprises an electric actuator  16   b  and a guide unit  18   b . In a state of the closure device  10   b  installed in an automotive vehicle, the guide unit  18   b  is entirely accommodated within the body of the automotive vehicle. The guide unit  18   b  includes two guide rails  20   b ,  22   b  extending in parallel to one another. The actuator  16   b  of the drive unit  14   b  is arranged at a guide rail  20   b . The guide rails  20   b ,  22   b  extend within a body of the automotive vehicle, in particular at least essentially parallel to a contour of the body. Furthermore, the guide unit  18   b  includes two carriages  24   b ,  26   b  arranged to be traversable on the guide rails  20   b ,  22   b , and on which the flap element  12   b  is arranged. The flap element  12   b  is disposed between the guide rails  20   b ,  22   b  and linked to the carriages  24   b ,  26   b  via three pivotable connecting elements  64   b ,  66   b ,  68   b.    
     In contrast to the closure device  10   a  shown in  FIGS.  1  to  10   , the drive unit  14   b  of the closure device  10   b  includes two gear units  28   b ,  38   b . The gear units  28   b ,  38   b  are provided for synchronous transmission of a drive movement generated by the actuator  16   b  to both carriages  24   b ,  26   b . Each of the gear units  28   b ,  38   b  is arranged at one of the guide rails  20   b ,  22   b . To convert a rotatory movement generated by the actuator  16   b  to a movement of the carriages  24   b ,  26   b , each of the carriages  24   b ,  26   b  has a rack  30   b ,  32   b . Each of the gear units  28   b ,  38   b  directly drives at least one pinion gear  34   b ,  36   b ,  42   b  each of which meshes with a rack  30   b ,  32   b  of a carriage  24   b ,  26   b . The racks  30   b ,  32   b  of the carriages  24   b ,  26   b  are provided to convert a rotatory movement of each of the pinion gears  34   b ,  36   b ,  42   b  to a movement of each carriage  24   b ,  26   b  along each of the guide rails  20   b ,  22   b.    
     To achieve synchronous operation of the gear units  28   b ,  38   b  and thus synchronous operation of the carriages  24   b ,  26   b , the drive unit  14   b  includes a first cross shaft  44   b  driven by a first one of said gear units  28   b . The first cross shaft  44   b  extends between the guide rails  20   b ,  22   b  and is rotatably supported in the guide rails  20   b ,  22   b . The first cross shaft  44   b  transmits a rotatory movement of a gear  46   b  of the first gear unit  28   b  to an input gear  48   b  of the second gear unit  38   b . The first cross shaft  44   b  has an actuator-side pinion gear  42   b  which meshes with the rack  30   b  of the actuator-side carriage  24   b  as a function of a traversing position of the actuator-side carriage  24   b . The actuator-side gear  42   b  of the first cross shaft  44   b  is provided to perform driving of the carriage  24   b  when it is traversed out of the engagement region of a first gear  34   b  driving the carriage  24   b.    
     Furthermore, the drive unit  14   b  has a second cross shaft  50   b . The second cross shaft  50   b  extends between the two carriages  24   b ,  26   b . The ends of the second cross shaft  50   b  are rotatably supported in the carriages  24   b ,  26   b . The cross shaft  50   b  is driven by a movement of the carriage  24   b . The movement of the carriage  24   b  is transmitted to the second carriage  26   b  by the second cross shaft  50   b . Each of the guide rails  20   b ,  22   b  of the guide unit  18   b  has a rack  52   b ,  54   b . The second cross shaft  50   b  has a pinion gear  56   b ,  58   b  at each of its ends, wherein each of the pinion gears  56   b ,  58   b  meshes with a rack  52   b ,  54   b  of one of the guide rails  20   b ,  22   b.    
     During opening or closing of a charging or tank flap, the guide rails  20   b ,  22   b  define the traversing path of the flap element  12   b . Each of the guide rails  20   b ,  22   b  has a traversing region  60   b  and a lifting region  62   b . During traversal of the flap element  12   b  along the traversal ranges  60   b  of the guide rails  20   b ,  22   b , the flap element performs a traversing movement at least essentially parallel to the body of the automotive vehicle. In the lifting region  62   b , the flap element  12   b  performs a lifting movement at least essentially perpendicular to the traversing movement. To guide the flap element  12   b  and to generate the traversal movement and the lifting movement of the flap element  12   b , each of the guide rails  20   b ,  22   b  has a guide groove  70   b ,  84   b . Two guiding pins  72   b ,  74   b  of the flap element  12   b  engage in the guide grooves  70   b ,  84   b . This achieves rail-guiding of the flap element  12   b  along the guide rails  20   b ,  22   b , or along the guide grooves  70   b ,  84   b  of the guide rails  20   b ,  22   b . The guiding pins  72   b ,  74   b  of the flap element  12   b  are passed through openings  76   b  in two connecting elements  64   b ,  66   b  through these two connecting elements  64   b ,  66   b  into the guide grooves  70   b ,  84   b  of the guide rails  20   b ,  22   b . The two connecting elements  64   b ,  66   b  are pivotable about the passed-through guiding pins  72   b ,  74   b  of the flap element  12   b . The third connecting element  68   b  is arranged on the flap element  12   b  to be pivotable about a pin  80   b  arranged on the third connecting element  68   b  in a torque-resistant manner. The carriages  24   b ,  26   b  include pivoting axles  82   b  protruding into corresponding openings of the connecting elements  64   b ,  66   b ,  68   b . The connecting elements  64   b ,  66   b ,  68   b  are pivotably arranged on the carriages  24   b ,  26   b  via the pivoting axles  82   b.    
     At the transition from the traversing region  60   b  to the lifting region  62   b  of the guide rails  20   b ,  22   b , the guide grooves  70   b ,  84   b  of the guide rails  20   b ,  22   b  have a change in direction of at least essentially 90°. The path of the guide grooves  70   b ,  84   b  in the lifting region  62   b  is thus at least essentially perpendicular to the path of the guide grooves  70   b ,  84   b  in the traversing region  60   b . During a closing operation, the guiding pins  72   b ,  74   b  of the flap element  12   b  follow the guide grooves  70   b ,  84   b , the change in direction of the guide grooves  70   b ,  84   b  causing pivoting of the connecting elements  64   b ,  66   b ,  68   b  about the pivoting axles  82   b  of the carriage elements  24   b ,  26   b . Pivoting of the connecting elements  64   b ,  66   b ,  68   b , in turn, causes a lifting movement of the flap element  12   b  linked to the connecting elements  64   b ,  66   b ,  68   b . In the closed position of the flap element  12   b , the connecting elements  64   b ,  66   b  assume a toggle-joint position thus achieving self-locking of the flap element  12   b  in the closed position. 
     During a closing operation, the flap element  12   b , due to the guiding by the guide rails  70   b ,  84   b , is first displaced in parallel to a body of the vehicle toward an access opening by a traversing movement, and is subsequently lifted into the access opening by a lifting movement, thus closing it. During an opening operation, the flap element  12   b  is first displaced in an almost perpendicular direction by a lowering movement opposite the lifting movement so that the flap element  12   b  is offset in parallel into the interior of the body of the automotive vehicle. The subsequent traversing movement causes the flap element  12   b  to be displaced in a direction almost parallel to the body, thus exposing an access opening. 
     To traverse the flap element  12   b  from a closed position into an open position even in a deenergized state of the actuator  16   b , an emergency unlocking device  86   b  is provided. To operate the emergency unlocking device  86   b , the latter includes an emergency unlocking pull  88   b . Pulling on the emergency unlocking pull  88   b  acts on a further element  90   b  connected to emergency unlocking pull  88   b  of the emergency unlocking device  86   b  on the carriage  24   b  in such a manner that it is displaced along the guide rail  20   b  by a certain distance. This moves the connecting elements  64   b ,  66   b  from the toggle joint position and releases the self-locking action of the flap element  12   b . 
     
       
         
           
               
             
               
                   
               
               
                 List of reference numerals 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 10 
                 closure device 
               
               
                 12 
                 flap element 
               
               
                 14 
                 drive unit 
               
               
                 16 
                 actuator 
               
               
                 18 
                 guide unit 
               
               
                 20 
                 guide rail 
               
               
                 22 
                 guide rail 
               
               
                 24 
                 carriage 
               
               
                 26 
                 carriage 
               
               
                 28 
                 gear unit 
               
               
                 30 
                 rack 
               
               
                 32 
                 rack 
               
               
                 34 
                 pinion gear 
               
               
                 36 
                 pinion gear 
               
               
                 38 
                 gear unit 
               
               
                 40 
                 cross shaft 
               
               
                 42 
                 pinion gear 
               
               
                 44 
                 cross shaft 
               
               
                 46 
                 gear 
               
               
                 48 
                 input gear 
               
               
                 50 
                 cross shaft 
               
               
                 52 
                 rack 
               
               
                 54 
                 rack 
               
               
                 56 
                 pinion gear 
               
               
                 58 
                 pinion gear 
               
               
                 60 
                 traversing region 
               
               
                 62 
                 lifting region 
               
               
                 64 
                 connecting element 
               
               
                 66 
                 connecting element 
               
               
                 68 
                 connecting element 
               
               
                 70 
                 guide groove 
               
               
                 72 
                 guiding pin 
               
               
                 74 
                 guiding pin 
               
               
                 76 
                 opening 
               
               
                 78 
                 opening 
               
               
                 80 
                 pin 
               
               
                 82 
                 pivoting axle 
               
               
                 84 
                 guide groove 
               
               
                 86 
                 emergency unlocking device 
               
               
                 88 
                 emergency unlocking pull 
               
               
                 90 
                 element