Abstract:
An adjustable vehicle seat ( 1 ) includes a seat part ( 2 ) and a backrest ( 3 ) which is pivotable relative to the seat part via a backrest adjustment fitting ( 5 ) and is lockable in a plurality of angular positions. A locking device ( 90 ) locks the seat part to a vehicle structure. An unlocking lever ( 30 ) transmits an unlocking movement to the locking device. A first interlock element ( 54 ), with the fitting unlocked, prevents a movement of the unlocking lever for unlocking the locking device and with the locking device unlocked, prevents an unlocking of the backrest adjustment fitting. The first interlock element, as a blocking lever, is connected to a transmission rod ( 60 ) for rotation therewith, to unlock the fitting. The unlocking lever has or interacts with a blocking element ( 36, 37 ) which, when the locking device; is unlocked, prevents a movement of the blocking lever for unlocking the backrest adjustment fitting.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a United States National Phase Application of International Application PCT/EP2013/065722 filed Jul. 25, 2013 and claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2012 015 287.6 filed Jul. 31, 2012, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to an adjustable vehicle seat comprising a seat part and a backrest, which can be pivoted relative to the seat part about a backrest pivot axis by means of at least one backrest setting fitting and can be locked in a plurality of angular positions, and at least one locking apparatus, by means of which the seat part can be locked to a vehicle structure 
       BACKGROUND OF THE INVENTION 
       [0003]    Adjustable vehicle seats which have a seat part and a backrest which is arranged pivotably on the seat part are known by use. In addition, a vehicle seat of this type has two backrest setting fittings, by means of which the backrest can be pivoted about a backrest pivot axis relative to the seat part, and by means of which the backrest can be locked to the seat part in a plurality of angular positions. 
         [0004]    Starting from a design position, in which a passenger can be seated and the backrest is approximately vertical, the vehicle seat can be transferred into a table position, in which the backrest rests on the seat part. Here, the rear side of the backrest lies approximately horizontally and the vehicle seat has the function of a table. 
         [0005]    Furthermore, it is known that the vehicle seat can be locked to the vehicle structure by means of two locking apparatuses which are attached in the rear region of the seat part. By way of unlocking of the two said locking apparatuses, the rear part of the vehicle seat can be released from the vehicle structure. By way of raising of the rear part of the vehicle seat and pivoting toward the front, the vehicle seat can be transferred into a tumble position, in which additional cargo area is produced. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention is based on the problem of improving a vehicle seat of the type mentioned at the outset, in particular of preventing simultaneous unlocking of the locking apparatuses and the backrest setting fittings. 
         [0007]    An adjustable vehicle seat according to the invention comprises a seat part and a backrest which can be pivoted relative to the seat part about a backrest pivot axis by means of at least one backrest setting fitting and can be locked in a plurality of angular positions, and at least one locking apparatus, by means of which the seat part can be locked to a vehicle structure. 
         [0008]    According to the invention, an unlocking lever is provided which transmits an introduced movement for unlocking to the at least one locking apparatus, a first interlocking element being provided which, when the backrest setting fitting is unlocked, prevents a movement of the unlocking lever for unlocking the locking apparatus, and which, when the locking apparatus is unlocked, prevents unlocking of the backrest setting fitting, the first interlocking element being configured as a blocking lever which is connected fixedly to a transmission rod so as to rotate with it, unlocking of the backrest setting fitting taking place during a rotation of the transmission rod, and the unlocking lever having a blocking element or interacting with a blocking element which, when the locking apparatus is unlocked, prevents a movement of the blocking lever for unlocking the backrest setting fitting. 
         [0009]    In this way, simultaneous unlocking of the locking apparatuses and the backrest setting fittings is not possible. 
         [0010]    Two backrest setting fittings are preferably provided here, and the transmission rod serves for simultaneous unlocking of both backrest setting fittings. 
         [0011]    When the backrest setting fitting is unlocked, the blocking lever preferably prevents a movement of the blocking element for unlocking the locking apparatus. 
         [0012]    A second interlocking element is advantageously provided which, when the backrest is approximately upright, prevents a movement of the unlocking lever for unlocking the locking apparatus. 
         [0013]    Here, when the backrest rests on the seat part, the second interlocking element permits a movement of the unlocking lever for unlocking the locking apparatus, and, when the locking apparatus is unlocked, prevents a pivoting movement of the backrest relative to the seat part. 
         [0014]    The second interlocking element is preferably configured as a leadthrough element of approximately cylindrical design and is fastened to the seat part in such a way that its cylinder axis is aligned with the backrest pivot axis. 
         [0015]    The leadthrough element advantageously has two leadthrough openings for leading through Bowden cables. Here, the Bowden cables serve for unlocking the locking apparatuses. 
         [0016]    On one end side, the leadthrough element has a diametrically running slot which, when the backrest rests on the seat part, is aligned with a blocking lug which is attached to the unlocking lever. 
         [0017]    Here, when the locking apparatus is unlocked, the blocking lug is situated within the slot. 
         [0018]    At least two locking apparatuses are preferably provided. 
         [0019]    Precisely two locking apparatuses are particularly advantageously provided. 
         [0020]    The unlocking lever can advantageously be pivoted about an actuating pivot axis which runs at right angles with respect to the backrest pivot axis. This results in a comparatively simple construction. 
         [0021]    A return spring is preferably provided which loads the unlocking lever constantly in the direction of a rest position, in which the unlocking lever is situated when the locking apparatus is locked. 
         [0022]    According to one advantageous refinement of the invention, the blocking element is designed as a blocking arm which is configured in one piece with the unlocking lever. 
         [0023]    According to a further advantageous refinement of the invention, the blocking element is designed as a blocking segment which is configured separately from the unlocking lever. 
         [0024]    The blocking segment and the unlocking lever are preferably mounted such that they can be pivoted about an identical actuating pivot axis. 
         [0025]    The present invention shall be explained in more detail on the basis of the following figures and exemplary embodiments, without the present invention being limited to these. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    In the drawings: 
           [0027]      FIG. 1  is a diagrammatic illustration of a vehicle seat according to a first exemplary embodiment in the design position; 
           [0028]      FIG. 2  is a diagrammatic illustration of the vehicle seat according to  FIG. 1  in the table position; 
           [0029]      FIG. 3  is a diagrammatic illustration of a vehicle seat according to  FIG. 1  in the tumble position; 
           [0030]      FIG. 4  is a perspective illustration of an interlocking unit according to the first exemplary embodiment; 
           [0031]      FIG. 5  is a side view of the interlocking unit according to  FIG. 4  in the design position; 
           [0032]      FIG. 6  is a front view of the interlocking unit according to  FIG. 4  in the design position; 
           [0033]      FIG. 7  is a side view of the interlocking unit according to  FIG. 4  in the table position; 
           [0034]      FIG. 8  is a front view of the interlocking unit according to  FIG. 4  in the table position; 
           [0035]      FIG. 9  is a side view of the interlocking unit according to  FIG. 4  in the tumble position; 
           [0036]      FIG. 10  is a front view of the interlocking unit according to  FIG. 4  in the tumble position; 
           [0037]      FIG. 11  is a diagrammatic illustration of a vehicle seat according to a second exemplary embodiment in the design position; 
           [0038]      FIG. 12  is a diagrammatic illustration of the vehicle seat according to  FIG. 11  in the table position; 
           [0039]      FIG. 13  is a diagrammatic illustration of a vehicle seat according to  FIG. 11  in the dump position; 
           [0040]      FIG. 14  is a perspective illustration of an interlocking unit according to the second exemplary embodiment; 
           [0041]      FIG. 15  is a side view of the interlocking unit according to  FIG. 14  in the design position; 
           [0042]      FIG. 16  is a front view of the interlocking unit according to  FIG. 14  in the design position; 
           [0043]      FIG. 17  is a side view of the interlocking unit according to  FIG. 14  in the table position; 
           [0044]      FIG. 18  is a front view of the interlocking unit according to  FIG. 14  in the table position; 
           [0045]      FIG. 19  is a side view of the interlocking unit according to  FIG. 14  in the dump position; and 
           [0046]      FIG. 20  is a front view of the interlocking unit according to  FIG. 14  in the dump position. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0047]    A vehicle seat  1  for a motor vehicle has a seat part  2  and a backrest  3 . The arrangement of the vehicle seat  1  within the vehicle and its usual driving direction define the direction information used in the following text. Here, a direction which is oriented perpendicularly with respect to the ground will be called the vertical direction in the following text and a direction perpendicular with respect to the vertical direction and perpendicular with respect to the driving direction will be called the transverse direction in the following text. 
         [0048]    The backrest  3  is attached to the seat part  2  such that it can be pivoted about a backrest pivot axis  6  which runs in the transverse direction, and comprises, inter alia, a backrest plate. By means of two backrest setting fittings  5  which are configured as latching fittings in the present case, the backrest  3  can be set in a plurality of discrete angular positions relative to the seat part  2 . A backrest setting fitting of this type is disclosed, for example, in DE 10 2004 041 449 B3, the disclosure of which in this regard is incorporated here expressly. 
         [0049]    A headrest which is of height-adjustable and inclination-adjustable configuration in the present case is attached at one end of the backrest  3 , which end faces away from the seat part. 
         [0050]    In the design position of the vehicle seat  1  which is shown in  FIG. 1  and  FIG. 11 , the backrest  3  is in an approximately vertical position. By way of unlocking of the backrest setting fittings  5  and pivoting of the backrest  3  into a horizontal position, the vehicle seat  1  can be transferred into a table position. In the table position which is shown in  FIG. 2  and  FIG. 12 , the backrest  3  rests on the seat part  2  and runs approximately parallel to the latter and parallel to the vehicle floor. 
         [0051]    According to a first exemplary embodiment which is shown in  FIG. 1  to  FIG. 10 , the seat part  2  is connected releasably to the vehicle structure. To this end, the seat part  2  has in each case one front foot  8  on both sides in the front region in the driving direction, which front foot  8  comprises a locking apparatus  90 . Furthermore, the seat part  2  has in each case one rear foot  9  on both sides in the rear region in the driving direction, which rear foot  9  comprises a locking apparatus  90 . A locking apparatus of this type is disclosed, for example, in WO 2004 069 585 A1, the disclosure of which in this regard is incorporated here expressly. 
         [0052]    In the design position and in the table position of the vehicle seat  1 , the locking apparatuses  90  are locked to pins which are attached to the vehicle structure. In order to transfer the vehicle seat  1  from the table position into a tumble position, the two locking apparatuses  90  of the rear feet  9  are unlocked simultaneously, as a result of which the rear feet  9  are released from the vehicle structure. 
         [0053]    In the tumble position which is shown in  FIG. 3 , the backrest  3  rests on the seat part  2  and runs approximately parallel to the latter. The vehicle seat  1  is folded forward and the backrest  3  and the seat part  2  are inclined relative to the vehicle floor. Here, the vehicle seat  1  is held in the tumble position by means of a strut  75 . 
         [0054]    For safety reasons, the two locking apparatuses  90  of the rear feet  9  must not be unlocked in the design position, but rather merely in the table position. In the tumble position, the locking apparatuses  90  are unlocked. The locking apparatuses  90  may therefore be unlocked only when the backrest  3  rests on the seat part  2 . 
         [0055]    For safety reasons, the two backrest setting fittings  5  must likewise not be unlocked in the tumble position, but rather merely in the table position and in the design position. The backrest setting fittings  5  may therefore be unlocked only when both locking apparatuses  90  are locked. 
         [0056]    The vehicle seat  1  comprises an interlocking unit  50  which will be described in greater detail in the following text and which ensures that the above-described unlocking processes can be carried out only in the correspondingly defined positions of the vehicle seat  1 . 
         [0057]    A transmission rod  60  which is assigned kinematically to the backrest  3  runs parallel to the backrest pivot axis  6 . The transmission rod  60  is connected to both backrest setting fittings  5  which are attached to the side of the vehicle seat  1  and serves for simultaneous unlocking of both backrest setting fittings  5 . The transmission rod  60  is arranged on the front side in the driving direction of the backrest plate. 
         [0058]    Unlocking of the backrest setting fittings  5  takes place by way of rotation of the transmission rod  60  by a predefined angle about its center axis which runs in the transverse direction. If the backrest setting fittings  5  are unlocked, the backrest  3  can be pivoted relative to the seat part  2  about the backrest pivot axis  6 . 
         [0059]    In the design position, in the table position and in the tumble position, the backrest setting fittings  5  are locked in each case. The backrest setting fittings  5  are unlocked merely during a pivoting movement of the backrest  3 . 
         [0060]    An unlocking unit is provided for simultaneous unlocking of both locking apparatuses  90  of the rear feet  9 , which unlocking unit is fastened to the backrest plate and is therefore likewise assigned kinematically to the backrest  3 . Here, the unlocking unit is arranged on the front side in the driving direction of the backrest plate. 
         [0061]    The unlocking unit  10  comprises a base plate  70  which is arranged largely parallel to the backrest plate. 
         [0062]    An unlocking lever  30  is mounted such that it can be pivoted about an actuating pivot axis  44 . The orientation of the actuating pivot axis  44  changes depending on the position of the backrest  3  relative to the seat part  2 . However, the actuating pivot axis  44  constantly runs approximately at right angles with respect to the backrest pivot axis  6 . A return spring  61  loads the unlocking lever  30  constantly in the direction of a rest position. 
         [0063]    On an arm which protrudes in the radial direction, the unlocking lever  30  has a belt eye  31 , into which a belt strap which serves as actuating element is hooked. The belt strap runs first of all from the belt eye  31  in the vertical direction to a deflection roller  73 . The belt strap is deflected on the deflection roller  73  counter to the driving direction and is guided to a belt opening in the backrest plate. The belt strap  62  is guided through the belt opening and protrudes out of the backrest  3  counter to the driving direction, that is to say toward the rear. 
         [0064]    By way of pulling on that end of the belt strap which protrudes out of the backrest  3 , the unlocking lever  30  is pivoted about the actuating pivot axis  44  in the direction of its actuating position. A limiting element (not shown) acts as a stop and limits the movement of the unlocking lever  30  after the actuating position is reached. 
         [0065]    A control gearwheel  20  is mounted such that it can be rotated about a control pivot axis  43  which runs parallel to the actuating pivot axis  44 . Approximately along half its circumference, the control gearwheel  20  has a control toothing system (not visible in the illustrations) which meshes with an unlocking toothing system  33  of the unlocking lever  30 . 
         [0066]    A first unlocking element  11  is mounted axially next to the control gearwheel  20  such that it can be rotated about the control pivot axis  43 . The first unlocking element  11  has, inter alia, a cylindrical segment-like region with a first circumferential face  55 , in which a first guide groove is formed. A first Bowden cable (not shown) is inserted into the first guide groove. At its end, the first Bowden cable has a first nipple which is hooked into a first Bowden cable hook-in means  13  of the first unlocking element  11 . 
         [0067]    The first Bowden cable runs from the first unlocking element  11  to a leadthrough element  80  which is fastened to the seat part  2 . The first Bowden cable runs further through a first leadthrough opening  81  of the leadthrough element  80  to one of the two locking apparatuses  90  in one of the rear feet  9 . 
         [0068]    A second unlocking element (not visible in the illustrations) is likewise mounted axially next to the control gearwheel  20  such that it can be rotated about the control pivot axis  43 . The second unlocking element has, inter alia, a cylindrical segment-like region with a second circumferential face, in which a second guide groove is formed. A second Bowden cable (not shown) is inserted into the second guide groove. At its end, the second Bowden cable has a second nipple which is hooked into a second Bowden cable hook-in means of the second unlocking element. 
         [0069]    The second Bowden cable runs from the second unlocking element to the leadthrough element  80  which is fastened to the seat part  2 . The second Bowden cable runs further through a second leadthrough opening  82  of the leadthrough element  80  to the other of the two locking apparatuses  90  in one of the rear feet  9 . 
         [0070]    If the unlocking unit  10  is situated in the starting position, the unlocking lever  30  is situated in the rest position, the control gearwheel  20  is situated in the locking position, the locking elements  11  are situated in the locking position, and the two locking apparatuses  90  are locked. If the unlocking unit  10  is situated in the activation position, the unlocking lever  30  is situated in the actuating position, the control gearwheel  20  is situated in the unlocking position, the unlocking elements  11  are situated in the unlocking position, and the two locking apparatuses  90  are unlocked. 
         [0071]    A control spring (not shown) is provided between the control gearwheel  20  and the first unlocking element  11 , which control spring loads the first unlocking element  11  relative to the control gearwheel  20  toward the unlocking position. A control spring is likewise provided between the control gearwheel  20  and the second unlocking element, which control spring loads the second unlocking element relative to the control gearwheel  20  toward the unlocking position. Here, the two control springs are configured in the present case as swivel pin springs and are plugged into corresponding openings in the unlocking elements  11  and the control gearwheel  20 . Here, the control gearwheel  20  is arranged between the first unlocking element  11  and the second unlocking element in the axial direction with regard to the control pivot axis  43 . The two control springs are situated in each case between the control gearwheel  20  and the associated unlocking element  11 . 
         [0072]    In the starting position of the unlocking unit  10 , a comparatively short end of the belt strap protrudes out of the backrest  3  toward the rear. This signals to a user that both locking apparatuses  90  are locked. 
         [0073]    By way of pulling on that end of the belt strap which protrudes out of the backrest  3 , the unlocking lever  30  is pivoted in the direction of the actuating position counter to the force of the return spring  61 . Here, the control gearwheel  20  is rotated in the direction of the unlocking position. After the control gearwheel  20  has passed through an idle travel, a driver  24  which is attached to the control gearwheel  20  comes into contact with a first counterstop of the first unlocking element  11  and with a second counterstop of the second unlocking element. 
         [0074]    In the present case, the driver  24  is attached in a region of the control gearwheel  20 , which region lies diametrically opposite the control toothing system, and protrudes in the axial direction on both sides from said control gearwheel  20 . The counterstops of the unlocking elements  11  are configured substantially as smooth surfaces which run in the radial and axial direction. 
         [0075]    By way of further pulling on the end of the belt strap, the control gearwheel  20  drives the unlocking elements  11 , as a result of which the latter are rotated in the direction of the unlocking position. Here, pulling takes place on the Bowden cables, as a result of which the locking apparatuses  90  are unlocked. This movement ends when the unlocking lever  30  bears against the limiting element and the unlocking unit is situated in the activation position. The belt strap then protrudes comparatively far out of the backrest  3 . This signals to a user that at least one of the two locking apparatuses  90  is unlocked. 
         [0076]    If the user then releases the belt strap, the unlocking lever  30  is pivoted in the direction of the rest position by way of the force of the return spring  61 . As a result, the control gearwheel  20  is also rotated in the direction of the locking position and the driver  24  moves away from the counterstops of the unlocking elements  11 . The unlocking elements  11  remain in the unlocking position, on account of the loading by way of the control springs. 
         [0077]    The movement of the unlocking lever  30  ends when a stop element  34  of the unlocking lever  30  bears against the first circumferential face  55  and/or against the second circumferential face. In the present case, the stop element  34  is attached to the arm of the unlocking lever  30 . The stop element  34  is arranged closer in the radial direction to the actuating pivot axis  44  than the belt eye  31  and protrudes in the axial direction on both sides from the arm. 
         [0078]    The unlocking lever  30  is now situated in the hold-open position and the unlocking unit  10  is situated in the display position. Although, in comparison to the activation position, the belt strap is pulled partially into the backrest  3 , it still protrudes comparatively far out of the backrest  3 . This signals to a user that at least one of the two locking apparatuses  90  is unlocked. 
         [0079]    The rear feet  9  of the vehicle seat  1  can then be removed from the vehicle structure, and the vehicle seat  1  can be folded forward into the tumble position. 
         [0080]    The vehicle seat  1  can tilt when the rear feet  9  are again placed onto the pins of the vehicle structure. Here, only one of the two locking apparatuses  90  locks to the associated pin in the vehicle structure, whereas the other of the two locking apparatuses  90  does not lock or locks only with a time delay to the assigned pin in the vehicle structure. 
         [0081]    For example, after the rear feet are placed onto the pins, the locking apparatus  90  which is connected to the first unlocking element  11  is unlocked, and the locking apparatus  90  which is connected to the second unlocking element is locked. During locking, the locking apparatus  90  which is connected to the second unlocking element pulls on the second Bowden cable, as a result of which the second unlocking element is rotated into the locking position. However, the first unlocking element  11  remains in the unlocking position. 
         [0082]    Here, the stop element  34  of the unlocking lever  30  loses contact with the second circumferential face, but still bears against the first circumferential face  55 . The unlocking lever  30  therefore remains in the hold-open position and the belt strap still protrudes comparatively far out of the backrest  3 . It is therefore signaled to a user that at least one of the two locking apparatuses  90  is unlocked. 
         [0083]    If the locking apparatus  90  which is connected to the first unlocking element  11  now also locks, it pulls on the first Bowden cable, as a result of which the first unlocking element  11  is also rotated into the locking position. Here, the stop element  34  of the unlocking lever  30  also loses contact with the first circumferential face  55 , and the unlocking lever  30  is rotated back into the rest position by way of the force of the return spring. Here, the control gearwheel  20  is also rotated back into the locking position. 
         [0084]    The unlocking unit is therefore situated in the starting position again. Here, the belt strap is pulled by the unlocking lever  30  into the backrest  3  to such an extent that only a comparatively short end of the belt strap is still visible from the outside. This signals to a user that both locking apparatuses  90  are locked. 
         [0085]    Close to the unlocking unit, a blocking lever  54  is attached on the transmission rod  60  and is connected fixedly to the latter so as to rotate with it. During unlocking of the backrest setting fittings  5 , the blocking lever  54  is also pivoted correspondingly. The unlocking lever  30  has a blocking arm  36  which interacts with the blocking lever  54 . 
         [0086]    In the design position which is shown in  FIG. 5  and  FIG. 6  and in the table position which is shown in  FIG. 7  and  FIG. 8 , the unlocking lever  30  is situated in each case in the rest position, the blocking arm  36  being situated laterally next to the blocking lever  54 . During unlocking of the backrest setting fittings  5 , the blocking lever  54  pivots laterally past the blocking arm  36 . Unlocking of the backrest setting fittings  5  is therefore possible in the design position and in the table position of the vehicle seat  1 . The blocking arm  36  likewise pivots past the blocking lever  54  during unlocking of the locking apparatuses  90 . Unlocking of the locking apparatuses  90  is therefore possible in the table position of the vehicle seat  1 . However, as will still be shown below, unlocking of the locking apparatuses  90  is not possible in the design position of the vehicle seat  1 . 
         [0087]    In the illustration according to  FIG. 5 , the blocking lever  54  is also shown additionally using dashed-dotted outlines in the pivoted state for unlocking the backrest setting fittings  5 . 
         [0088]    During the unlocking of the backrest setting fittings  5 , that is to say as long as the backrest setting fittings  5  are unlocked, the blocking lever  54  is situated in front of the blocking arm  36 . During the attempt to unlock the locking apparatuses  90 , the blocking arm  36  of the unlocking lever  30  comes into contact with the blocking lever  54 . Unlocking of the locking apparatuses  90  when the backrest setting fittings  5  are unlocked is therefore not possible. 
         [0089]    In the tumble position which is shown in  FIG. 9  and  FIG. 10 , the unlocking lever  30  is situated in the hold-open position. Here, the blocking arm  36  is situated immediately in front of the blocking lever  54 . During the attempt to unlock the backrest setting fittings  5 , the blocking lever  54  comes into contact with the blocking arm  36 . Unlocking of the backrest setting fittings  5  is therefore not possible in the tumble position of the vehicle seat  1 . 
         [0090]    The leadthrough element  80  which is fastened to the seat part  2  is of approximately cylindrical design, its cylinder axis being aligned with the backrest pivot axis  6 . The leadthrough element  80  is therefore assigned kinematically to the seat part  2 . During pivoting of the backrest  3  from the design position into the table position, the leadthrough element  80  therefore rotates relative to the unlocking unit. 
         [0091]    The leadthrough element  80  has a diametrically running slot  78  on an end side which points in the transverse direction to the interior of the vehicle seat  1 , that is to say faces the unlocking unit. The leadthrough element  80  is arranged in such a way that, when the vehicle seat  1  is situated in the table position, the slot  78  is aligned with a blocking lug  38  which is attached to the unlocking lever  30 . 
         [0092]    When the vehicle seat  1  is situated in the design position, the slot  78  runs obliquely with respect to the movement direction of the blocking lug  38 , as shown in  FIG. 4  and  FIG. 6 . During the attempt to unlock the locking apparatuses  90 , the blocking lug  38  of the unlocking lever  30  comes into contact with the cylinder shell of the leadthrough element  80 . Unlocking of the locking apparatuses  90  is therefore not possible when the vehicle seat  1  is situated in the design position. 
         [0093]    When the vehicle seat  1  is situated in the table position, the slot  78  runs in the same direction as the movement direction of the blocking lug  38 , as shown in  FIG. 8 . The slot  78  is not visible in this illustration. During unlocking of the locking apparatuses  90 , the blocking lug  38  pivots into the slot  78 . Unlocking of the locking apparatuses  90  is therefore possible in the table position of the vehicle seat  1 . 
         [0094]    In the tumble position which is shown in  FIG. 10 , the unlocking lever  30  is situated in the hold-open position. Here, the blocking lug  38  of the unlocking lever  30  is situated within the slot  78  of the leadthrough element  80 . In the tumble position, as described above, unlocking of the backrest setting fittings  5  is not possible. Even if the backrest setting fittings  5  were unlocked in the tumble position, a pivoting movement of the backrest  3  relative to the seat part  2  would not be possible. In this case, the edge regions of the slot  78  would come into contact with the blocking lug  38  and prevent a pivoting movement of the backrest  3  relative to the seat part  2 . 
         [0095]    According to a second exemplary embodiment which is shown in  FIG. 11  to  FIG. 20 , the seat part  2  is connected fixedly to the vehicle structure. The vehicle seat  1  according to the second exemplary embodiment is of largely identical design to the vehicle seat  1  of the first exemplary embodiment. In the following text, approximately only differences between the first and the second exemplary embodiment will be described. 
         [0096]    In the front region on both sides in the driving direction, the seat part  2  is articulated on the vehicle structure by way of in each case one four-bar linkage  7 . Furthermore, as is also the case in the first exemplary embodiment, the seat part  2  has in each case one rear foot  9  on both sides in the rear region in the driving direction, which rear foot  9  comprises a locking apparatus  90 . 
         [0097]    By way of pivoting of the backrest  3  into a horizontal position, the vehicle seat  1  can likewise be transferred from a design position which is shown in  FIG. 11  into a table position which is shown in  FIG. 12 . From the described table position, the vehicle seat  1  can be transferred into a dump position which is shown in  FIG. 13 . In the dump position of the vehicle seat  1 , the backrest  3  rests on the seat part  2  and the seat part  2  is pivoted toward the front in the driving direction and downward in the vertical direction by means of the four-bar linkage  7 . Here, the locking apparatuses  90  are locked to two different pins on the vehicle structure which are arranged further forward in the driving direction. 
         [0098]    When the vehicle seat  1  is situated in the dump position, that is to say when the locking apparatuses  90  are locked, the two backrest setting fittings  5  must also not be unlocked for safety reasons. 
         [0099]    The vehicle seat  1  according to the second exemplary embodiment which can be transferred into the dump position therefore additionally has a transmission unit (not shown) which, when the vehicle seat  1  is situated in the dump position, supplies a corresponding signal to the interlocking unit  50 . The transmission unit comprises substantially a transmission Bowden cable which, when the vehicle seat  1  is situated in the dump position, pivots a transmission lever which can be pivoted about the actuating pivot axis  44 . Here, the transmission lever interacts with an additional blocking segment  37  which is likewise mounted such that it can be pivoted about the actuating pivot axis  44 . Here, the blocking segment  37  is arranged largely coaxially with respect to the unlocking lever  30 . 
         [0100]    During a transition from the design position which is shown in  FIG. 15  and  FIG. 16  into the table position which is shown in  FIG. 17  and  FIG. 18 , the leadthrough element  80  experiences a rotation relative to the backrest  3 , as in the first exemplary embodiment, as a result of which the slot  78  is aligned with the blocking lug  38  which is attached to the unlocking lever  30 . 
         [0101]    In the illustration according to  FIG. 15 , the blocking lever  54  is also shown in the pivoted state for unlocking the backrest setting fittings  5 , additionally using dashed-dotted outlines. 
         [0102]    During a transition from the table position which is shown in  FIG. 17  and  FIG. 18  into the dump position which is shown in  FIG. 19  and  FIG. 20 , first of all, the locking apparatuses  90  are opened by way of pivoting of the unlocking lever  30 . Here, the unlocking lever  30  drives the blocking segment  37  and pivots it in front of the blocking lever  54 . The blocking segment  37  therefore prevents a movement of the blocking lever  54  and therefore unlocking of the backrest setting fittings  5  while one of the locking apparatuses  90  is open. As long as one of the locking apparatuses  90  is open, the unlocking lever  30  remains in the hold-open position and therefore also holds the blocking segment  37  in front of the blocking lever  54 . 
         [0103]    After the dump position is reached, the locking apparatuses  90  lock to the front pins on the vehicle structure, and the unlocking lever  30  pivots back into its rest position. 
         [0104]    In the dump position, however, the blocking segment  37  is held in its position in front of the blocking lever  54  by the transmission lever which is pivoted by the transmission Bowden cable, and remains there. The blocking segment  37  therefore prevents a movement of the blocking lever  54  and therefore unlocking of the backrest setting fittings  5  while the vehicle seat  1  is situated in the dump position. 
         [0105]    During the return from the dump position which is shown in  FIG. 19  and  FIG. 20  into the table position which is shown in  FIG. 17  and  FIG. 18 , first of all the locking apparatuses  90  are opened by way of pivoting of the unlocking lever  30 . Here, the unlocking lever  30  remains in the hold-open position as long as one of the locking apparatuses  90  is open. 
         [0106]    During the movement of the seat part  2  toward the rear, the transmission Bowden cable releases the transmission lever which thereupon pivots back in a spring-loaded manner. As a result, the transmission lever also releases the blocking segment  37  which, however, is still held in the position in front of the blocking lever  54  by way of the unlocking lever  30 . 
         [0107]    After the table position is reached, the unlocking lever  30  pivots back into its hold-open position and therefore also releases the blocking segment  37 . Thereupon, the blocking segment  37  pivots back in a spring-loaded manner and releases the blocking lever  54 . 
         [0108]    The features which are disclosed in the above description, the claims and the drawings can be of significance both individually and in combination for the realization of the invention in its different refinements. 
         [0109]    While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.