CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 USC 119 to German Patent Application No. 10 2009 006 387.0 filed on Jan. 28, 2009, the entire disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a device for electrically adjusting a vehicle seat, with articulated constructions arranged on different sides of the vehicle seat, and with at least one electric motor with a gear mechanism coupled thereto for moving the articulated constructions, and with at least one mechanism for locking the articulated constructions. 
         [0004]    2. Description of the Related Art 
         [0005]    An electric motor with a gear mechanism unit coupled thereto customarily is provided for electrically adjusting articulated constructions arranged on the right and left side of the vehicle seat. The articulated constructions are moved by the gear mechanism unit to adjust the vehicle seat with regard to the height adjustment of the vehicle seat, the inclination adjustment of a seat cushion of the vehicle seat or the inclination position of a backrest of the vehicle seat. The electric motor with a gear mechanism unit coupled thereto adjust the articulated construction on the one side of the vehicle seat. The electric adjustment unit also forms a lock for the articulated construction on the corresponding side of the vehicle seat when the electric adjustment unit is in the inoperative state to keep the vehicle seat securely in its position. The articulated construction on the other side of the vehicle seat also has to be locked to ensure secure locking of the vehicle seat even in the event of a crash and the high forces occurring in the process. It is known for this purpose to use a force transmission tube that couples the left and the right articulated construction to each other and thereby transfers the locking force to the side without the electric adjustment unit. The force transmission tube is relatively heavy and also is flexible. Therefore the force transmission tube leads to an asymmetrical positioning of the vehicle seat due to the one-sided locking in the event of a crash. 
         [0006]    DE 199 11 786 C2, JP 2008 024014 A and EP 0 245 650 A2 each describe an inertia drive for a crash locking of an adjustment device of a motor vehicle seat. 
         [0007]    U.S. Pat. No. 6,902,234 B2, U.S. Pat. No. 4,040,591, GB 2 065 464 A and WO 99/05000 all relate to various embodiments of mechanical crash locks for adjustment devices of vehicle seats. 
         [0008]    DE 199 53 630 C5, DE 101 37 298 C1, DE 103 06 827 B4, DE 103 06 828 B4 and EP 1 121 263 B1 each relate to a crash lock with the use of an additional load path in the case of a vehicle seat. 
         [0009]    It is the object of the present invention to develop a device of the type described that ensures a precise adjustment of the vehicle seat and secure locking of the vehicle seat in the event of a crash. 
       SUMMARY OF THE INVENTION 
       [0010]    The invention relates to a device with a gear mechanism for moving the articulated construction arranged on a particular side of the vehicle seat and a mechanism for locking the articulated construction arranged on each of the different sides of the vehicle seat. 
         [0011]    Each articulated construction preferably is assigned a dedicated locking mechanism and hence the articulated constructions arranged on the different sides of the vehicle seat are locked directly. The locking takes place on the respective side of the vehicle seat. Hence, the locking mechanisms and the gear mechanisms can be designed to be correspondingly smaller and lighter than if a single mechanism is used. 
         [0012]    The locking of the articulated constructions takes place on both sides of the vehicle seat. Therefore, no asymmetry is produced either when adjusting the vehicle seat or in the event of a crash. 
         [0013]    The gear mechanism and the mechanisms for locking the articulated construction preferably are arranged symmetrically with respect to a surface that is arranged in the longitudinal direction of the vehicle seat and in the widthwise center of the vehicle seat. The surface therefore constitutes the seat center surface. 
         [0014]    The gear mechanisms arranged on the different sides of the vehicle seat, in particular the gear mechanisms arranged symmetrically with respect to the seat center surface, can be driven in different ways. For example, a single electric motor may be coupled to the gear mechanisms, and the electric motor may be arranged centrally with respect to the symmetrical surface. Thus, the electric motor may be connected to the gear mechanism by flexible shafts. On the other hand, two electric motors may be provided. One electric motor may be arranged on the one vehicle side and may be coupled to the gear mechanism arranged there, and the other electric motor may be arranged on the other vehicle side and may be coupled to the gear mechanism arranged there. These two electric motors preferably are in arranged symmetrically with respect to the symmetrical surface. The electric motors preferably are connected by a synchronization shaft to ensure synchronism of the electric motors. 
         [0015]    The gear mechanisms used in the device preferably are of identical design. In the situation in which each gear mechanism is assigned an electric motor, the respective electric motor and the gear mechanism assigned thereto constitute a constructional unit. 
         [0016]    The symmetrical arrangement of the system give rise to an increase in comfort. Furthermore, the symmetrical locking units contribute to the positive crash behaviour of the system. This also enables the weight of the system to be reduced and possibly also the costs. 
         [0017]    The mechanism for locking the associated articulated construction can be designed in different ways. For example, the locking mechanism may be a self-locking mechanism, a centrifugal lock, an inertia lock and/or an electrically triggerable lock. The mechanism for locking the associated articulated construction may be formed separately to the assigned gear mechanism or may be integrated into the gear mechanism. In the latter case, the gear mechanism is a self-locking gear mechanism. The arrangement can be structurally compact when the mechanism for locking the associated articulated construction is integrated into the gear mechanism. 
         [0018]    The articulated constructions function to adjust the vehicle seat with regard to a height adjustment of the vehicle seat, an inclination adjustment of a seat cushion of the vehicle seat and/or inclination adjustment of a backrest of the vehicle seat. The respective articulated constructions may differ in design. According to preferred designs, the respective articulated construction is designed as a single-part lever that is mounted pivotably at both ends, or as a toggle lever that is mounted pivotably at both ends. 
         [0019]    Further advantages and features of the invention emerge from the dependent claims and from the description below of a number of exemplary embodiments of the invention without being restricted thereto. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a schematic three-dimensional view of the mounting of a height-adjustable seat part of a vehicle seat together with a device according to the invention for electrically adjusting the height of the vehicle seat. 
           [0021]      FIG. 2  is a schematic diagram of the essential components of the device used in the embodiment of  FIG. 1  for electrically adjusting the vehicle seat. 
           [0022]      FIG. 3  is a schematic diagram as in  FIG. 2  for a modified device for electrically adjusting the vehicle seat. 
           [0023]      FIG. 4  is a schematic side view of the seat part of  FIG. 1  mounted in the seat rails, with an additionally illustrated mounting of the backrest of the vehicle seat in the seat part and a design of the vehicle seat for changing the inclination of a seat cushion of the seat part. 
           [0024]      FIG. 5  is a side view of a further modified vehicle seat illustrated to show the seat part thereof and backrest thereof, but with the mounting of the seat part in seat rails on both sides in each case via a rear single-part lever and a front toggle lever. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]      FIG. 1  is a substantially horizontally arranged seat part  1  of a vehicle seat  2 , for example a driver&#39;s seat or passenger&#39;s seat of a passenger vehicle. 
         [0026]    The seat part has a right side  3  and a left side  4  with respect to the direction of travel of the motor vehicle. A front lever  5  and a rear lever  6  are provided on each of the right and left sides  3  and  4 . Each rear lever  6  has a lower end in a rail upper part  7  of the vehicle seat  2  in a manner to pivot about a joint G 1 . The two rail upper parts  7  are arranged parallel to each other and are positioned in the longitudinal direction of the vehicle. The rail upper parts  7  are mounted displaceably in rail lower parts  8  that are mounted in a stationary manner to the motor vehicle floor (not illustrated). Locking elements (not illustrated) can selectively lock the rail upper parts  7  in defined positions with respect to the rail lower parts  8  and therefore lock the vehicle seat  2  in different longitudinal positions. 
         [0027]    The upper end of each rear lever  6  is mounted in the rear region of the seat part  1 , in a manner to pivot about a joint G 2 . 
         [0028]    The upper end of each front lever  5  is mounted in the region of the front end in the vehicle seat  2  to pivot about a joint G 3 . The lower end of each front lever  5  is mounted in a front region of the associated rail upper part  7  to pivot about a joint pin G 4 . 
         [0029]    The levers  5  and  6  are inclined obliquely to the rear from the lower bearings G 4  and G 1  of the levers  5  and  6  and are aligned parallel to each other. 
         [0030]      FIG. 1  does not show a backrest of the vehicle seat  2 , which is arranged at a rear region of the seat part  1 .  FIG. 1  also does not show elements of the vehicle seat that may be provided to change the inclination of a component of the seat cushion of the seat part  1 . 
         [0031]    The seat part  1  of  FIG. 1  is adjusted in height by introducing a torque in the region of the pivots G 2  of the two rear levers  6 . The rear levers  6  thus are pivoted in the region of their upper end relative to the seat part  1 . As a result the parallel link construction causes a substantially parallel raising or lowering of the seat part  1 . 
         [0032]      FIGS. 1 and 2  illustrate the device  9  for electrically adjusting the seat part  1  of the vehicle seat  2 . The device  9  has two substantially identical gear mechanisms  10  disposed respective on the sides  3  and  4  of the seat part  1  in addition to the articulated levers  5  and  6 . The gear mechanisms  10  are operative for moving the rear levers  6  on the respective sides  4  and  5 . The device  9  further has locking mechanisms  11  assigned respectively to the gear mechanisms  10  for locking the associated lever  6 . The gear mechanisms  10  and the locking mechanisms  11  are arranged symmetrically with respect to a seat center plane  12  that extends perpendicularly to half the seat part width in the longitudinal direction of the seat part  1 . A single electric motor  13  is coupled to the two gear mechanisms  10 . The electric motor  13  is arranged centrally and symmetrically with respect to the seat center plane  12  and is connected to the gear mechanisms  10  via flexible shafts  14 . The locking mechanism  11  for locking the respective assigned lever  6  is, for example, a self-locking mechanism, a centrifugal lock and/or an inertia lock. The locking mechanism  11  can be integrated in the assigned gear mechanism  10 . In this case, the gear mechanism  10  preferably is a self-locking gear mechanism. The gear mechanism  10  of  FIG. 1  has a mechanical main drive pinion  15  that acts on the rear lever  6  in the region of the joint pins G 2 , which are connected in a rotationally fixed manner to the respective rear lever  6  and the main drive pinion  15 . 
         [0033]    The height adjustment illustrated in  FIG. 1  of the seat part  1 , which is in particular the seat cushion of the vehicle seat, alternatively could take place at any of the other joints G 1 , G 3  or G 4 . 
         [0034]      FIG. 3  shows a modification of the embodiment of  FIG. 2 . More particularly, two electric motors  13  are provided in the embodiment of  FIG. 3  instead of the one electric motor in the embodiment of  FIG. 2 . Each electric motor  13  in  FIG. 3  is arranged on the side of the respective gear mechanism  10  and directly drives the respective gear mechanism  10 . The electric motors  13  are arranged symmetrically with respect to the seat center plane  12 , and each electric motor  13  forms a constructional unit with the associated gear mechanism  10 . The two electric motors  13  optionally may be connected by a synchronization shaft  16 . 
         [0035]      FIGS. 4 and 5  illustrate vehicle seats  2  that are modified from the design of  FIG. 1  with respect to the points of engagement of the mechanical main drive pinions  15  on both sides of the vehicle seat  2 . The respective electric motor  13 , the respective gear mechanism  10  and the respective locking mechanism  11  of the preceding illustrations are omitted from  FIGS. 4 and 5  for simplicity. 
         [0036]    In the embodiment according to  FIG. 4 , the seat part  1  is mounted via the levers  5  and  6  substantially as in the embodiment of  FIG. 1 . In contrast to the embodiment of  FIG. 1 , the front half of the seat part  1  has an adjustment device for adjusting the seat cushion inclination. More particularly, the vehicle seat  2  of  FIG. 4  has a seat cushion  17  with opposite left and right sides and opposite front and rear ends. The rear end of the seat cushion  17  is mounted at the opposite left and right sides to seat side structures  18  of the seat part  1  and can pivot about joint pins G 6 . Front toggle lever assemblies  19  are mounted in the region of the front end of the seat cushion  17  on each side of the seat cushion  17 . Each toggle lever assembly  19  has lever arms  20  and  21  that are connected pivotably to each other at a joint point G 8 . The end of each lever arm  20  opposite the lever arm  21  is connected pivotably to the seat cushion  17  at a joint pin G 7 . Each lever arm  21  has a lower end connected pivotably to the associated seat side structure  18  at a joint point G 9 . 
         [0037]    A backrest  22  is mounted to rear regions of the respective seat side structures  18  and can be pivoted about a joint point G 10  to adjust the inclination of the backrest  22 . 
         [0038]    In the embodiment according to  FIG. 4 , the point of engagement of the mechanical main drive pinion  15  of the seat cushion height adjuster can be on the joints G 1 , G 2 , G 3  or G 4 . The point of engagement of the mechanical main drive pinion  15  of the seat cushion inclination adjuster can be on the joints G 6 , G 7 , G 8  or G 9 . The point of engagement of the mechanical main drive pinion  15  of the backrest inclination adjuster can be on the joint G 10 . 
         [0039]    The embodiment of  FIG. 5  has a seat cushion  17 , which, in contrast to the embodiment according to  FIG. 4 , is not provided as a subregion of the seat part  1 . Rather the entirety of the seat part  1  of  FIG. 5  can be adjusted in height and inclination. For this purpose, toggle lever assemblies  5  are arranged on both sides of the seat part  1 . Each toggle lever assembly  5  has an the upper lever arm  23  and a lower lever arm  24  that are connected pivotably to one another at a joint point G 5 . The end of the upper lever arm  23  opposite the lower lever arm  24  is mounted in the seat part  1  to pivot about a joint pin G 3 . The end of the lower lever arm  24  opposite the upper lever arm  23  is mounted in the rail upper part  7  to pivot about the joint pin G 4 . 
         [0040]    In the embodiment according to  FIG. 5 , the point of engagement of the mechanical main drive pinion  15  of the seat part height adjuster is on the joints G 1 , G 2 , G 3  or G 4 . The point of engagement of the mechanical main drive pinion  15  of the seat part inclination adjuster can be on the joints G 3 , G 4  or G 5 . The point of engagement of the mechanical main drive pinion  15  of the backrest inclination adjuster is on the joint G 10 . 
         [0041]    All of the joints G 1  to G 10  are joints the permit the respective component to pivot at the joint about a horizontal axis arranged transversely with respect to the longitudinal direction of the vehicle.
A device is provided for electrically adjusting a vehicle seat ( 1). The device has left and right articulated constructions ( 6, 6) arranged respectively on left and right sides ( 3, 4) of the vehicle seat ( 1). The device also has at least one electric motor ( 13) coupled to left and right gear mechanisms ( 10) for moving the respective left and right articulated constructions ( 6, 6) and left and right locking mechanisms ( 11) for locking the respective left and right articulated constructions ( 6, 6). The design permits a precise adjustment of the vehicle seat and secure locking of the vehicle seat in the event of a crash.