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BACKGROUND AND SUMMARY OF THE INVENTION  
       [0001]     This invention relates to a motor vehicle body having at least two doors, which are arranged on one side of the vehicle, and a releasable body B-column, which is arranged between the two doors on the side of the vehicle in a position fixed on the body. The invention also relates to a motor vehicle having a motor vehicle body according to the invention.  
         [0002]     German patent specification 464 139 discloses a motor vehicle with a motor vehicle body having two doors, which are arranged on one side of the vehicle, and a releasable body B-column. The body B-column is arranged between the two doors on the side of the vehicle in a position fixed on the body. In order to be able to load a stretcher into the interior of the vehicle, the body B-column is fastened to the rear of the two doors. The B-column can be provided at the top and bottom with latches which are inserted into the roof frame and base frame of the vehicle body. The front door is fastened to an A-column and opens counter to the normal forward direction of travel. The rear of the two doors, to which the B-column is fastened, is fastened to a C-column and opens in the direction of travel.  
         [0003]     U.S. Pat. No. 2,212,674 discloses a releasable body B-column. The B-column is attached in a vehicle floor by means of a hook and is fastened to the roof frame by means of a latching lever.  
         [0004]     German laid-open specification DE 38 10 762 A1 discloses a motor vehicle body, in which a B-column is integrated into a rear door opening counter to the direction of travel. The B-column integrated into the rear door includes locking devices, for example bolts, which can interact with a roof frame and a floor frame.  
         [0005]     An object of the invention is to provide a flexible motor vehicle body which, on the one hand, provides protection for the vehicle occupants and, on the other hand, is to be easily loaded even with bulky articles.  
         [0006]     According to the invention, a motor vehicle body having at least two doors, which are arranged on one side of the vehicle, and a releasable body B-column, which is arranged between the two doors on the side of the vehicle in a position fixed on the body, is provided. A first of the two doors can be opened either by means of first articulation means along a first trajectory or by means of second articulation means along a second trajectory.  
         [0007]     The opening of the doors is thereby designed in a flexible manner, and the first trajectory can be provided, for example, for a normal opening counter to the forward direction of travel. This avoids, in the driving mode, the known disadvantages of doors opening in the direction of travel. The second trajectory can be designed for a maximum possible opening of the door in order, by removal of the B-column, to be able to load bulky goods. For example, the first trajectory predetermines a conventional pivoting of the door and the second trajectory can bring about a pivoting or else displacement, if appropriate in the manner of a parallelogram and together with the B-column.  
         [0008]     According to one feature of the invention, the first articulation means for the pivotable articulation of the first door are provided on the B-column.  
         [0009]     This achieves a normal opening of the door counter to the direction of travel and, with regard to a conventional, modern vehicle, a change of the opening process during normal operation is not required.  
         [0010]     In this case, the B-column stiffens the motor vehicle body, so that, firstly, the lack of structural rigidity and sealing problems of vehicles without a B-column are avoided and, secondly, impact protection is provided and easy fastening of the seatbelt to the B-column is possible.  
         [0011]     According to another feature of the invention, the second articulation means for the pivotable articulation of the first door are provided on at least one point of the body that is different from the B-column.  
         [0012]     The second articulation means for the alternative, second trajectory for opening the door with the effect of easy loading of bulky articles can be provided, for example, in the rear door frame region or else on the roof frame. The B-column may be, for example, removed or pivoted together with the first door. For example, multi-joint hinges could be used as the second articulation means to provide more freedom in the selection of the trajectory.  
         [0013]     According to another feature of the invention, the first articulation means are designed as at least one door hinge which connects the first door to the B-column.  
         [0014]     In this manner, with regard to a conventional vehicle, a change to the door itself is not required. This is of importance in particular for the retrospective conversion of a vehicle, for example of vehicles for the disabled.  
         [0015]     According to another feature of the invention, the second articulation means are designed as at least one pivoting clip and means are provided in order either to connect the first door pivotably to the body structure by means of the pivoting clip or to open it up in the region of the pivoting clip.  
         [0016]     A pivoting clip makes it possible for the second trajectory of the door to be configured in a freer manner, and nevertheless a stable, simple construction can be realized.  
         [0017]     According to another feature of the invention, the pivoting clip is connected pivotably to the body structure and, by means of a door lock, can optionally act on the first door.  
         [0018]     This also ensures that, with regard to a conventional vehicle, only slight changes are required, since the optional connection of the pivoting clip to the body structure takes place via a door lock which is present in any case. For example, the pivoting clip is latched to the door by means of the door lock, and, during opening, the door is held via the door lock and further supporting surfaces on the pivoting clip and door.  
         [0019]     According to another feature of the invention, the door lock of the first door can act on a locking eye which is connected pivotably to the body structure by means of the lockable pivoting clip.  
         [0020]     This measure also reduces the required changes with regard to conventional vehicles, since the door is connected to the pivoting clip by means of the locking eye, which is present in any case. During normal operation, the pivoting clip or the locking eye can be locked directly to the door frame.  
         [0021]     According to another feature of the invention, the first door is connected pivotably to the B-column in the region of a front door edge and can optionally be connected pivotably to the body structure in the region of an opposite, rear door edge.  
         [0022]     This achieves a conventional door opening for maximum safety of the occupants during normal operation and, in the case of pivoting about the rear door edge, a maximum door opening for easy loading can be achieved. An opening angle of the first, rear door and of the second, front door is then expediently at least 90°.  
         [0023]     According to another feature of the invention, means are provided for the controlled connection of the second articulation means to the first door or the body structure and for the subsequent release of the B-column from the body structure.  
         [0024]     For example, if required by a driver, a controlled, consecutive unlocking of the B-column from the remaining body structure, the locking of the door lock to the locking eye and the opening up of the pivoting clip can take place.  
         [0025]     According to another feature of the invention, the B-column can be connected, on the one hand, to a roof frame and, on the other hand, to a sill by means of tension rods, compression rods and/or intercepting hooks.  
         [0026]     This achieves a stable, simple construction, for example in a manner similar to a lock for a convertible roof.  
         [0027]     The problem on which the invention is based is also solved by a motor vehicle having a motor vehicle body according to the invention.  
         [0028]     Further features and advantages of the invention emerge from the claims and the description below of a preferred embodiment in conjunction with the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]      FIGS. 1A, 1B  and  1 C show perspective views of a section of a motor vehicle body according to the invention in the case of normal door opening,  
         [0030]      FIGS. 2A and 2B  show sectional views of the motor vehicle body of  FIGS. 1A  to  1 C in the case of normal door opening,  
         [0031]      FIGS. 3A, 3B  and  3 C show views of the motor vehicle body of  FIGS. 1A, 1B  and  1 C during the opening of the doors to provide a maximum door opening,  
         [0032]      FIGS. 4A and 4B  show sectional views of the motor vehicle body of  FIGS. 1A, 1B  and  1 C during the opening of the doors to provide a maximum door opening,  
         [0033]      FIG. 5  shows a schematic illustration of a releasable body B-column according to the invention, and  
         [0034]      FIG. 6  shows a schematic illustration of a control device for the motor vehicle body according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]     The illustrations of  FIGS. 1A, 1B  and  1 C show a side part  10  of a motor vehicle body according to the invention having a first, rear door  12 , a second, front door  14  and a releasable B-column  16 . The front door  14  is fastened to the side part  10  in the region of an A-column by means of conventional door hinges and a door lock of the front door  14  engages in a locking eye  18  on the B-column  16 . The rear door  12  is fastened to the B-column  16  in a conventional manner per se by means of two door hinges and consequently opens, like the front door  14 , counter to the forward direction of travel. In the driving mode, such an opening counter to the direction of travel has, for example, the advantage that the doors  12 ,  14  can be closed by the relative wind and consequently cannot spring open unexpectedly. The door lock of the rear door  12  engages in a locking eye  20  which is arranged in the region of a C-column of the side part  10 .  
         [0036]     As can be gathered from  FIGS. 1A, 1B  and  1 C, an opening of the doors in the normal operation illustrated takes place in an entirely conventional manner, and an opening of the front door  14  and of the rear door  15  is possible independently of each other. By means of the B-column  16 , the roof frame of the side part  10  is supported against the sill region, and the motor vehicle body consequently has a rigidity which is not reduced in comparison to conventional bodies and provides protection in the event of an impact. For example, a seatbelt may also be fastened to the B-column  16 .  
         [0037]     In the sectional views of  FIGS. 2A and 2B , the B-column  16  and the rear door  12  and a rear wing of the side part  10  can be seen in each case. As has already been described, the rear door  12  is articulated on the B-column  16  by means of conventional door hinges  22 . A door lock  24  of the rear door  12  acts in a known manner on a locking eye  26  which is arranged on the rear edge of the door frame in the side part  10 . The locking eye  26  is connected to a pivoting clip  28  which, for its part, is connected pivotably to the side part  10  at an articulation point  30 . In the case of the normal door opening which is illustrated in  FIGS. 2A and 2B , the locking eye  26  and/or the pivoting clip  28  is locked, so that a relative movement between the rear edge of the door frame of the side part  10  and the locking eye  26  cannot occur. In consequence, in the closed position according to  FIG. 2A , the door  12  is held securely on the side part  10 . Since, in the normal operation illustrated, the B-column  16  is also connected securely to the side part  10  and, for example, is locked thereto, in the event of a vehicle impact the motor vehicle body according to the invention behaves in the same manner as a conventional motor vehicle body without a releasable B-column.  
         [0038]     The views of  FIGS. 3A, 3B  and  3 C show the side part  10  with the doors  12  and  14  and the B-column  16  of the motor vehicle body of  FIGS. 1A, 1B  and  1 C in the case of an opening of the doors  12  and  14  to provide a maximum door opening.  
         [0039]     As can be seen in  FIG. 3A , first of all the front door  14  is opened to an opening angle of approximately 90°. Then, provided that the door lock of the rear door  12  is locked to the locking eye, the means of locking the B-column  16  to the sill and to the roof frame of the side part  10  are opened up. The means of locking the locking eye and/or the pivoting clip to the side part  10  can then be opened up, so that, as can be seen in  FIG. 3B , the rear door  12  together with the B-column  16  can be pivoted about the C-column of the side part  10  by means of the pivoting clip  28 . In this case, the B-column  16  is held on the door  12  by means of the conventional door hinges.  
         [0040]     As can be gathered from the side view of  FIG. 3C , the rear door  12  can also be opened by an angle of 90° by means of the pivoting clip  28 , so that the entire, maximum door opening is available in the side part  10  for loading bulky articles or, for example, removing the seats without the B-column  16  being able to obstruct a loading process.  
         [0041]     Analogously to the sectional views of  FIGS. 2A and 2B , the sectional views of  FIGS. 4A and 4B  show the B-column  16 , the rear door  12  and the rear wing of the side part  10  in the case of an opening of the rear door  12  to provide a maximum door opening counter to the normal forward direction of travel of the motor vehicle.  
         [0042]     The sectional view of  FIG. 4A  shows the closed state of the rear door  12 , which has already been illustrated in  FIG. 2A . Starting from the state of  FIG. 4A , first of all the front door has to be opened, then the means of locking the B-column  16  to the side part  10  can be released and a means of locking the locking eye  26  and/or the pivoting clip  28  to the side part  10  is released. In this case, the means of locking the B-column  16  must only be released when the door lock  24  of the rear door  12  has latched into the locking eye  26 .  
         [0043]     The rear door  12  can then be pivoted about the articulation point  30  of the pivoting clip  28  to an opening angle of approximately 90°. As has already been described, the B-column  16  is held in the process on the door  12  by means of the conventional door hinges  22 . In addition to the fastening of the rear door  12  to the pivoting clip  28  by means of the door lock  24  and the locking eye  26 , further supporting elements  32  (merely indicated by dashed lines in  FIG. 4A ), can be provided in order to hold the rear door  12  securely on the pivoting clip  28  during opening.  
         [0044]     The schematic illustration of  FIG. 5  illustrates the B-column  16  and the rear door  12 . The B-column  16  has recesses  34  and  36  which can be pushed onto matching projections on the side part of the motor vehicle body and ensure that the B-column  16  is held securely on the side part. In order to lock the B-column  16  to the side part, an intercepting hook  38  is provided in the region of the upper recess  36  and can engage in a matching opening on the side part  10 . The intercepting hook  38  is connected to a lever  40  by means of a tension rod. Actuation of the lever  40  makes it possible, in a similar manner to the locking of a convertible roof, for the intercepting hook  38  and therefore the B-column  16  to be braced against the side part. A latch  42 , which is likewise connected to the lever  40  by means of an actuating rod, is provided in the region of the lower recess  34  of the B-column  16 . When the lever  40  is actuated, the intercepting hook  38  is therefore firstly pulled downward in  FIG. 5  and at the same time the latch  42  is pushed downward. The B-column  16  can therefore be securely anchored on the side part by means of the latch  42  and the intercepting hook  38 . The actuation of the lever  40  can either take place manually or by means of an electrically activatable device, for example a lifting magnet  44 .  
         [0045]     The schematic illustration of  FIG. 6  illustrates a control system in order to trigger in a controlled manner the unlocking and locking processes to be undertaken for the alternative trajectories of the rear door  12 . A central control unit  46  contains, as input signals, a command to prepare the opening of the rear door  12  to provide a maximum door opening. Such a command can be initiated, for example, by a driver. Furthermore, the control unit  46  receives input signals concerning the driving state of the vehicle. For example, the unlocking of the B-column  16  can only take place when the vehicle is stationary and the ignition is switched off. In addition, the control unit  46  receives an input signal concerning whether the door lock  24  of the rear door  12  is securely latched to the locking eye  26  on the side part.  
         [0046]     If the required boundary conditions for the opening of the rear door  12  to provide a maximum door opening are provided, the control unit  46  first of all sends a command to the lifting magnet  44  which then, as has been illustrated schematically in  FIG. 5 , releases the means of locking the B-column  16  to the side part of the motor vehicle body. At the same time, the control unit  46  can release the means of locking the pivoting clip  28  (illustrated in  FIGS. 4A and 4B ) and/or the locking eye  26  to the motor vehicle body. After the means of locking the B-column  16  and the pivoting clip and/or the locking eye  26  have been released, the rear door  12  can then be opened rearward about the pivoting clip, as illustrated in  FIG. 3B . The control unit  46  expediently blocks the locking of the door lock  24  to the locking eye  26  as soon as the means of locking the B-column to the side part of the motor vehicle body have been released. This prevents the rear door  12  from inadvertently being released from the locking eye  26  and the pivoting clip by actuation of a door handle.  
         [0047]     After the door  12  has been closed again and the B-column  16  is arranged at the designated position between the roof frame and sill of the side part, the control unit  46 , upon an appropriate request command, ensures the locking of the B-column  16  to the side part and the locking of the pivoting clip and/or of the locking eye  26  to the door frame of the side part. The blocking of the door lock  24  can thereupon be cancelled and the rear door  12  can be opened again in normal, conventional manner. At the same time, for example, the ignition of the motor vehicle can be opened up again for the driving mode.

Summary:
A motor vehicle body has at least two doors, which are arranged on one side of the vehicle, and a releasable body B-column, which is arranged between the two doors on the side of the vehicle in a position fixed on the body. A first of the two doors can be opened either by way of hinges along a first trajectory or by way of a pivoting clip along a second trajectory. The invention may be used, for example, for a variable door-opening system for easy loading with bulky goods.