Abstract:
A vehicle seat having a seat surface and a seatback is tiltable about a transversely extending pivot axis. The seatback is arranged to be tiltable from an upright seat position into a tilted resting position. In order to achieve a comfortable setting of the headrest in all seat positions and resting positions, the seatback has an automatically driven height adjustment apparatus and an automatically driven tilt adjustment apparatus, each positioned within the seatback.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to Application No. 102 09 189.7, filed in the Federal Republic of Germany on Mar. 4, 2002, which is expressly incorporated herein in its entirety by reference thereto. 
     FIELD OF THE INVENTION 
     The present invention relates a vehicle seat. 
     BACKGROUND INFORMATION 
     German Published Patent Application No. 196 44 021 describes a vertically adjustable headrest for a vehicle seat. The headrest has a cushion carrier that engages from above into the back of the vehicle seat and is adjustable vertically by an electric linear drive. It is disadvantageous here that the adjustment capability of the headrest is not sufficient to achieve comfortable support of the head in all seat positions. 
     German Published Patent Application No. 31 16 208 describes a surgical chair having a headrest, the position of which is manually adjustable. The operation of this adjustment apparatus is very complex. Adjustment of the headrest can be performed only with difficulty by the seat occupant alone. 
     German Published Patent Application No. 100 22 441 describes a seatback for a vehicle seat having a so-called active headrest. The headrest height can be set manually. By a two-armed lever positioned in the seatback, in the event of a rear-end crash the headrest is accelerated toward the occupant&#39;s head because the seat occupant&#39;s body presses on the lever. This headrest as well is insufficiently adjustable, so that comfortable head support is not ensured. 
     It is an object of the present invention to provide a vehicle seat, having an adjustable seatback, which has a headrest that may ensure comfortable and secure head support in every possible seat position, may have a compact configuration, and may be as easy as possible to operate. 
     SUMMARY 
     The above and other beneficial objects of the present invention may be achieved by providing a vehicle seat as described herein. 
     In an example embodiment, the vehicle seat has a height adjustment apparatus and a tilt adjustment apparatus. By the height adjustment apparatus, the height of the headrest is set in preselectable fashion so that good head support may be ensured for short and tall persons. In addition, the vehicle seat has a tilt adjustment apparatus that sets and/or modifies the tilt of the headrest and/or the spacing of the headrest from the seat occupant. The tilt adjustment apparatus is automatically driven and may be controlled such that the headrest may be moved into a freely preselectable position. To ensure a maximally compact and, in particular, robust arrangement of the tilt adjustment apparatus, the latter may be positioned in integrated fashion in the seatback. The tilt adjustment apparatus is joined to a cushion carrier of the headrest and acts on the latter to pivot the headrest about a pivot axis located in the seatback and extending transversely, so that the tilt adjustment apparatus modifies and/or adapts the spacing of the headrest from the seat occupant. 
     The placement of the pivot axis in the seatback may be selected so that upon adjustment of the headrest tilt, no vertical motion relative to the head may occur. The pivot axis may be positioned in a region corresponding approximately to the rotation point of head when sitting up into the reading position. Optimum adjustment of the headrest may thereby be achieved. Especially in the case of a vehicle seat having a pivotable backrest that may be pivoted between an upright seat position and a tilted reclining position, it is possible to ensure an optimum and/or comfortable setting of the headrest for all possible seat positions. With the seatback pivoted back, it is possible for the seat occupant to assume a resting position and for the headrest also to pivot back correspondingly. It is also possible, with the seatback pivoted back, to assume a relaxed reading position by swinging the headrest farther forward. Comfortable head support may therefore be guaranteed in every seat position, and the seat occupant may relax his or her neck muscles. 
     For convenient operation, provision may be made for the height adjustment device and/or tilt adjustment device to have a drive motor, e.g., an electric or pneumatic drive motor, etc. A preselected position may be easily arrived at, and/or a pleasant seating position for the seat occupant may be established, by activating the tilt adjustment device and/or height adjustment device, for example, by pressing a button. 
     An example embodiment provides for the height adjustment device to have a slide that may be moved up and down by a drive motor in the seatback. The slide may be arranged to retain the headrest cushion carrier by having a receptacle into which the cushion carrier of the headrest may be inserted, e.g., may be snap-locked, from above. The height of the headrest is thus varied as the slide moves up and/or down. 
     An example embodiment provides for the height adjustment apparatus to be mounted on the tilt adjustment apparatus, e.g., for the height adjustment apparatus to be joined by the tilt adjustment apparatus to a part of the seatback frame or to the seatback frame itself. In order to modify the tilt and/or the position of the headrest, the tilt adjustment apparatus pivots the height adjustment apparatus about a pivot axis. Since the headrest and the cushion are mounted on the height adjustment apparatus, the tilt adjustment apparatus acts indirectly, via the height adjustment apparatus, on the headrest in order to adjust the tilt and/or position. 
     The placement of the tilt adjustment apparatus and the height adjustment apparatus in the seatback may provide that the headrest may be adjusted with very little noise. In addition, the tilt adjustment apparatus and/or the height adjustment apparatus may have low-noise drives, e.g., an electric geared motor or spindle drive, etc., in each case, in order to ensure low-noise adjustment of the headrest. 
     It may be possible to use the vehicle seat according to the present invention in passenger cars, in buses, and in watercraft or rail vehicles, etc. Use of the vehicle seat according to the present invention as a comfortable passenger seat in aircraft is also provided. 
     Further features and example embodiments of the present invention are described below with reference to the Figures. The features and feature combinations described above and described below are usable not only in the particular combination indicated but also in other combinations or in isolation, without departing from the scope of the present invention. 
     Further example embodiments of the present invention are illustrated in and explained with reference to the Figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a vehicle seat having a tilted seatback, with the headrest in the resting position. 
     FIG. 2 illustrates a vehicle seat having a tilted seatback, with the headrest in the reading position. 
     FIG. 3 is a side view of the seatback with the tilt adjustment apparatus. 
     FIG. 4 schematically illustrates the frame of the seatback. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates a vehicle seat  1  with a person at rest. The vehicle seat is arranged as an adjustable vehicle seat with an upright seat position, as is usual with a conventional vehicle seat, and an adjustable resting position. It has a backrest  14  having a cushion  15 , a seat cushion  11 , and a footrest  13 . A headrest  2  is positioned at the upper end of seatback  14 . In the resting position illustrated in FIG. 1, footrest  13  is raised as compared with an upright seat position, so that the seat occupant may conveniently rest his or her feet on footrest  13 . Seat cushion  11  is adjustable as to tilt by a seat cushion adjuster  12 , so that seat cushion  11  constitutes a seat surface with adjustable tilt. 
     Backrest  14  is pivotable about a pivot axis extending transversely to the seat surface, so that a more-upright or a more-reclined seat position may be selected. 
     Headrest  2  positioned at the upper end of seatback  14  has a cushion carrier  22  and a head cushion  21 . The head cushion is shaped such that it may constitute an optimum support for the back of the seat occupant&#39;s head and his or her neck. The headrest thus may ensure planar support of the head. Cushion carrier  22  retains the head cushion by a joint positioned in the upper region of head cushion  21 , so that the position of head cushion  21  relative to cushion carrier  22  is adjustable. 
     Cushion carrier  22  is pivotable, by a tilt adjustment apparatus  4 , about a pivot axis  43  positioned in seatback  14 . The seat occupant may thus move from the resting position illustrated in FIG. 1 into a more-upright reading position illustrated in FIG.  2 . Pivot axis  43  is positioned in the seatback in the region of the rotation point about which the seat occupant&#39;s head rotates while sitting up. No motion is therefore performed relative to the head as a result of the pivoting of headrest  2 , and support may be optimal not only in the end positions but also in every intermediate position of cushion carrier  22 . 
     FIG. 3 is a cross-sectional side view through seatback  14 . Cushion carrier  22  of headrest  2  engages from above through openings  16  into seatback  14  and is mounted in tilt adjustment apparatus  4 . The latter is received entirely in the interior of seatback  14 , cushion  15  of the seatback serving for sound insulation. Tilt adjustment apparatus  4  is mounted on frame  17  of seatback  14  by pivot bearings  42 . 
     A geared electric motor  44  engages between seatback frame  17  and tilt adjustment apparatus  4  and pivots the latter about pivot axis  43 , as also illustrated in FIG. 4, where frame  17  of seatback  14  is illustrated in perspective along with tilt adjustment device  4  and height adjustment device  3 . Seatback frame  17  is U-shaped, and has centeredly positioned and end-located crossmembers  18 ,  19  for reinforcement. Positioned at the upper end of the seatback frame is a housing having openings  16  in which drive motor  44  of tilt adjustment apparatus  4  is received. Tilt adjustment apparatus  4  has two tubes  41   a ,  41   b  positioned in parallel. One end of each of these tubes  41   a ,  41   b  is mounted by a respective rotary bearing  42 , indirectly via a spacer  49 , on center crossmember  19  of seatback frame  17 . The other end of tube extends into the housing positioned at the top of the seatback frame, and is joined there to the respective other tube via of a coupler. Drive motor  44  acts via a linkage and a toothed segment on the coupler, for simultaneous and parallel pivoting of the two tubes  41   a  and  41   b . The pivot angle of tubes  41   a ,  41   b  is limited by stops. 
     Pivot axis  43  of the headrest extends through pivot bearings  42  and is defined by their placement. Spacer  49  determines the spacing of pivot bearings  42  from center crossmember  19  and thus the location of pivot axis  43  within seatback  14 . By modifying the spacer, the location of pivot axis  43  may be varied and/or adapted to seatback frame  17  such that the pivot axis approximately coincides with the natural rotation point of the head while sitting up. 
     Height adjustment device  3  is mounted on tubes  41   a ,  41   b  such that as tubes  41   a  and  41   b  pivot, height adjustment device  3  is also pivoted. A slide  33  of height adjustment device  3  is guided in longitudinally displaceable fashion on the tubes. Slide  33  is automatically moved up or down by a threaded spindle  31  that is driven by a drive motor  32 . This spindle drive is self-locking, so that the position arrived at by height adjustment device  3  is automatically held. 
     Slide  33  has two receptacles  34  into which the rod assembly of cushion carrier  22  may be inserted from above. Receptacles  34  snap-lock releasably to cushion carrier  22  so that the latter is held securely in slide  33  and, together with the latter, may be moved up and down and/or may be pivoted by tilt adjustment apparatus  4 .