Abstract:
A device to actuate a drive gear of an adjustment mechanism of a vehicle seat includes a stepped switching mechanism manually operable in two directions by means of a swiveling lever that is rotationally connected with the drive gear in order to rotate it. The rotational connection between the stepped switching mechanism and the drive gear is releasable to facilitate a greater range of seat back adjustment.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to a device that allows both quick and convenient adjustment of a seat back position relative to a seat bottom over a long adjustment path as well as fine-stepped adjustment.  
         BACKGROUND OF THE INVENTION  
         [0002]    In a device of the type disclosed in DE 198 55 004 A1, for adjustment of a seat back, a stepped switching mechanism with a self-limiting drive actuated by a swiveling lever is constantly engaged. Various drives allow the adaptation to various adjustment conditions. When elements of a vehicle seat are displaced by small adjustment steps, the stepped switching mechanism must be actuated unnecessarily often to achieve large displacement. Actuation along long adjustment paths is thus inconvenient and time-consuming.  
         SUMMARY OF THE INVENTION  
         [0003]    Based on this state of the art, it is the task of the invention to create a device of the known type so that it allows both quick and convenient adjustment of a seat back position relative to a seat bottom over a long adjustment path as well as fine-stepped adjustment.  
           [0004]    The adjustment of a vehicle seat can be accomplished with or without a stepped switching mechanism. The mechanism connecting the stepped switching mechanism with the adjustment device is simple and inexpensive.  
           [0005]    The invention features a device to actuate a drive gear of an adjustment mechanism of a seat with a switching mechanism manually operable in two directions by means of a swiveling lever that is rotationally connected with said drive gear in order to rotate it. A release mechanism provides a releasable rotational connection between the switching mechanism and the drive gear, for providing a rotating connection between the switching mechanism and the drive gear. In a preferred embodiment, an intermediate gear is provided between the switching mechanism and the drive gear. Providing an intermediate gear also promotes positive actuation  
           [0006]    Separation of the drive gear and the switching mechanism may be provided by means of a stepped switching mechanism swiveling lever that can be actuated without the exertion of a large actuation force. The lever may include the release mechanism.  
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0007]    These and other features and advantages of the present invention will be better understood by reading the following detailed description, taken together with the drawings wherein:  
         [0008]    [0008]FIG. 1 is a schematic side view of a vehicle seat with a tilt adjustment mechanism and an actuation device for the seat back according to the present invention;  
         [0009]    [0009]FIG. 2 is an enlarged side view of an adjustment mechanism and an actuation device as shown in FIG. 1 in its initial position;  
         [0010]    [0010]FIG. 3 is the view as shown in FIG. 2 illustrating the adjustment mechanism and actuation device areas;  
         [0011]    [0011]FIG. 4 is a side view as in FIG. 2 with the coupled swiveling lever used to release the rotating connection between the adjustment mechanism and actuation device; and  
         [0012]    [0012]FIG. 5 is a side view s in FIG. 2 with the rotating connection in the released position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]    In the figures, the same parts receive the same reference designations, and are distinguished from one another using apostrophes as necessary.  
         [0014]    A seat back  2  is mounted to a seat body  1  so that it may swivel about a horizontal tilt axis  3   b . The tilt of the seat back  2  may be adjusted by means of an adjustment device  3 . The adjustment device  3  is driven manually by an actuation device  4  via an intermediate gear  5 . The actuation device  4  includes a well known stepped switching mechanism  4   c  that is not shown in detail in the Figures.  
         [0015]    The intermediate gear  5  is mounted on a swiveling lever  6  that is free to rotate about a rotation axis  4   b  of the stepped switching mechanism  4   c . The seat back  2  is pre-tensioned along the direction of vehicle travel by a spring  7  mounted on the seat body  1 .  
         [0016]    The stepped switching mechanism  4   c  includes a drive take-off gear  4   d  that is constantly engaged with the intermediate gear  5 . The stepped switching mechanism  4   c  offers adjustment movements in opposing directions. It is operated exclusively by a swiveling lever  4   a . Drive forces from the adjustment mechanism  3  acting in response on the stepped switching mechanism  4   c  will not cause displacement of the stepped switching mechanism  4   c  even when the swiveling lever  4   a  is in the neutral central setting.  
         [0017]    The swiveling lever  4   a  is mounted free to rotate about the same swivel axis  4   b  as the swing lever  6 . The free end of the swiveling lever  4   a  includes an operation button  4   e  that acts on a linkage rod  4   f  mounted along the longitudinal central plane of the swiveling lever  4   a . When the swiveling lever  4   a  is in its central position as shown in FIG. 2, the opposite end of the linkage rod  4   f  is positioned opposite an aperture  6   b . This aperture  6   b  is provided in an arc-shaped crosspiece  6   c  surrounding the drive take-off gear  4   d  that is formed on the swing lever  6 .  
         [0018]    The linkage rod  4   f  is held away from the aperture  6   b  via a pressure spring  4   g . A spring  6   a  grips the swing lever  6  with one end, while the other end rests on the seat body  1 . The spring  6   a  holds the intermediate gear  5  in contact with a drive gear  3   a  of the adjustment mechanism  3 .  
         [0019]    The swiveling lever  4   a  may be displaced upward or downward from its neutral position as far as the positions shown by dotted lines in FIG. 3 and designated as  4   a . Displacement of the swiveling lever  4   a  either upward or downward from its central position causes rotation of the drive take-off gear  4   d  that is converted into a stepped adjustment of the seat back  2  by means of the intermediate gear  5  and the drive gear  3   a  mounted on the tilt axis  3   b . Upon multiple actuations of the swiveling lever  4   a  upward or downward from the central position, the tilt of the seat back  2  may be altered, for example, through the tilt range designated by 2′.  
         [0020]    When the seat back  2  is to be adjusted through a greater tilt angle than that shown in FIG. 3, the actuation button  4   e  is pressed into the neutral central position of the swiveling lever  4   a , as shown in FIG. 4. The linkage rod  4   f  then penetrates the aperture  6   b  in the swing lever  6 .  
         [0021]    When the swiveling lever  4   a  is raised while the actuation button  4   e  is depressed, the swing lever  6  rotates about the axis  4   b , and the intermediate gear  5  is displaced away from the drive gear  3   a . The drive gear  3   a  is thus free to rotate. This causes the spring  7  to move the seat back in a forward direction and to press the seat back  2  against the back of the seat occupant, if present. The seat back  2  can then be roughly manually adjusted (by the seat occupant, for example) into the position designated with 2″ in FIG. 5, as is normal with a raster adjustment mechanism.  
         [0022]    After the intermediate gear  5  is engaged with the drive gear  3   a , the now present tilt position of the seat back is locked by the stepped switching mechanism  4   c . In any of these tilt positions of the seat back  2 , fine adjustment of the tilt of the seat back is possible by means of the stepped switching mechanism  4   c  as previously described.  
         [0023]    Although the present invention has been explained utilizing an automobile type seat, this is for exemplary purposes only and not a limitation of the present invention which can be implemented in any type of seat.  
         [0024]    Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention that is not to be limited except by the claims which follow.