Abstract:
Vehicle seat ( 1 ), in particular for a two-door automobile, with a seat back ( 3 ) and a headrest ( 3   a,    5, 5   a ) integrated into the seat back, wherein one section ( 3   a ) of a seat-back frame forms a carrying structure of the headrest, and the headrest comprises a cushion carrier part ( 5 ) mounted in such a way that it can move with respect to the seat-back frame when the seat back is tilted forward, so that the overall length of the seat back is reduced when tilted forward with respect to the resting position.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a vehicle seat, in particular for a two-door automobile. 
     The seats of modern motor vehicles are known to be equipped with headrests, which in particular are intended to prevent the head from being thrown back, with corresponding injuries to the cervical vertebrae, as a result of head-on collisions or being run into from the rear. In limousines headrests of this kind as a rule are separate components inserted into the seat back. 
     Especially in sports cars, however, headrests are in many cases fully integrated, being basically a tapered extension of the seat back that often comprises a distinct upholstered section. In order to ensure that these headrests satisfy the safety requirements even for tall drivers, the seat backs with fully integrated headrests frequently reach almost up to the roofliner of the car. 
     In the case of sports cars, this introduces problems in tilting the seat back forward, as is necessary to allow access to the back seat of automobiles that have such a seat, or to the storage space behind the front seats. 
     SUMMARY OF THE INVENTION 
     It is thus the object of the invention to disclose an improved vehicle seat of the generic kind, in which the seat back can be tilted forward without colliding with the roofliner or the sun visor even though the car is of flat construction. 
     This object is achieved by a vehicle seat comprising the features of claim 1. The invention includes the essential idea of reducing the effective overall length of the seat back while the seat is tilted forward with respect to the resting state of the seat, i.e. the state in which the back is locked in the upright position. It further includes the idea that this reducing or shortening is enabled by providing a separate part of the headrest that is movable with respect to the integrated seat-back structure. 
     In preferred embodiments of the vehicle seat, this mobility is implemented by a pivoted connection or a sliding connection, in particular with a guide-gate mechanism, or by a combination of the two, disposed between the seat-back frame and the separate headrest part, which in the following will be called the cushion carrier part. 
     In another preferred embodiment an actuating element is disposed on the seat-back frame or immediately adjacent thereto, which brings about or at least initiates the movement of the cushion carrier part. Embodiments are also possible in which the cushion carrier part is grasped with the hand prior to tilting the seat back forward and is guided manually into the position that makes tilting of the seat back unproblematic, but with the actuating element mentioned above the manual work of the user is reduced and the usefulness of the proposed solution is further enhanced. 
     The actuating element in a further development of the idea in accordance with the invention is connected to an unlocking element of the seat back in such a way that it responds to disengagement of the seat back and moves the cushion carrier part into the position that enables the seat back to be tilted forward or initiates this movement. 
     In another, preferred further development the actuating element is associated with the seat-back frame in such a way that it responds to a pivoting movement of the seat back that exceeds a predetermined angular amount. One result is that a movement of the cushion carrier part does not occur when the seat back is displaced within normal limits, and another is that its movement during tilting of the seat back can be controlled in dependence on the angle of inclination, and if desired can be made approximately proportional to the latter. 
     In order to transmit forces between the actuating element and the mechanism for moving the cushion carrier part, in particular a mechanical traction- or pressure-transmitting element is provided, for instance a Bowden cable or connecting-rod arrangement. 
     The cushion carrier part is advantageously locked to the seat-back frame in the resting position by a catch connection, which is released in particular by way of the actuating element. 
     As mentioned above, in special embodiments the movement of the cushion carrier part is not driven, or at least not over the entire movement path, by the actuating element, which instead merely initiates the movement. In one useful further development of these embodiments, the driving element for the movement is a spring element disposed between the seat-back frame and the cushion carrier part, which pushes the cushion carrier part out of the resting position into the position suitable for tilting the seat back forward. 
     In an embodiment alternative to this one, a spring element is provided to support the movement of the cushion carrier part back into its resting position. In this embodiment the movement out of the resting position into the tilted-seat-back position is either mediated by the above-mentioned traction-or pressure-transmitting element or effected manually. 
     The above-mentioned pivoted connection is constructed in an advantageous embodiment as a linkage connection comprising two axles disposed substantially horizontally in the seat-back frame, about each of which rotates at least one lever the free end of which is attached to the cushion carrier part. When the lever is caused to swivel about the axle by the actuating element, the result is a swiveling (and lowering) of the cushion carrier part. In this case the tension- or pressure-transmitting element that constitutes the connection to the actuating element can act directly at the two axles. 
     In another development of this embodiment, however, a separate connection can be provided between the swiveling lever or levers on the one axle and the swiveling lever or levers on the other axle, by way of a rod that mediates traction and pressure. This connecting rod transmits every movement of the one lever or pair of levers to the other lever or pair of levers. 
     In another advantageous embodiment, the seat-back frame and the cushion carrier part are connected to one another by way of a combined pivoting and sliding mechanism, which on the one hand comprises an axle bearing a swiveling lever or pair of such levers and on the other hand comprises a curved guide gate. With this mechanism, the lower end of the cushion carrier part is pivoted away from the seat-back frame, into a lowered position, while the upper end is guided in the curved gate so that in the first segment of its path it moves substantially forward and in a second segment, substantially downward toward the seating surface. 
     In an aesthetically appealing and therefore preferred embodiment the cushion carrier part is connected to the seat-back frame over substantially the entire outer circumferential region by means of a flexible or foldable cuff, which conceals the mechanical elements by which the movement is driven and even when the cushion carrier part is in the tilted-forward position largely preserves the visual impression of a fully integrated seat-back/headrest unit. 
     As for the rest, other advantages and useful features of the invention will be apparent from the subclaims and the following description of preferred exemplary embodiments with reference to the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 Is a sketch-like drawing of the headrest section of a vehicle seat back with integrated headrest according to one embodiment of the invention in the position suitable for tilting the seat back forward, 
     FIGS. 2 a  and  2   b  are drawings of the headrest section of the vehicle seat according to FIG. 1 in the resting position and, respectively, in the tilted-forward position with a covering cuff removed, 
     FIGS. 3 a  and  3   b  are drawings of the mechanical construction of the headrest section of a vehicle seat according to one embodiment of the invention in resting and tilted-forward position, respectively, as a sectional drawing along a vertical (FIG. 3 a ) or a horizontal (FIG. 3 b ) plane of section, 
     FIGS. 4 a  to  4   c  are perspective partial views to explain the mechanical construction of the headrest section of a vehicle seat according to a first embodiment of the invention, 
     FIGS. 5 a  and  5   b  are perspective partial views to explain the mechanical construction of the headrest section of a vehicle seat slightly modified from the embodiment according to FIGS. 4 a  to  4   c,    
     FIGS. 6 a  to  6   c  are perspective partial views to explain the mechanical construction of the headrest section of a vehicle seat according to a second embodiment of the invention, 
     FIGS. 7 a  to  7   c  are perspective partial views to explain the mechanical construction of the headrest section of a vehicle seat according to a third embodiment of the invention, 
     FIGS. 8 a  to  8   c  are perspective partial views to explain the mechanical construction of the headrest section of a vehicle seat according to a fourth embodiment of the invention, and 
     FIGS. 9 a  to  9   c  are detail views to explain the actuating mechanism for movement of the cushion carrier part of the headrest for a vehicle seat according to one embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIG. 1 the headrest section of a seat back  3  of a vehicle seat  1  is shown in perspective, in the position suitable for tilting the seat back  3  forward. A cushion carrier part  5 , which comprises a headrest cushion  5   a  separate from the upholstery of the rest of the seat, is displaced forward (toward the left in the drawing) and downward with respect to a headrest section  3   a  of the seat back  3 , after the seat back has been disengaged by means of an unlocking lever  9  so as to be tilted forward. 
     A covering cuff  7 , which connects the circumference of the headrest section  3   a  to that of the cushion carrier part  5 , conceals a mechanism described in detail below, which mediates the lowering of the cushion carrier part  5  with respect to the seat back  3 . 
     FIGS. 2 a  and  2   b , in drawings corresponding to those of FIG. 1, show the resting state of the vehicle seat  1  with seat back  3  locked upright (FIG. 2 a ) for comparison with the state in which the seat back is ready to be tilted forward (FIG. 2 b ). In the drawing of FIG. 2 b  the covering cuff  7  (FIG. 1) has been removed so that parts of a seat-back frame  11  and additional parts of the mechanism for moving the cushion carrier part  5  can be seen. The dot-dashed lines A 1 , A 2  denote the axes of rotation of two axles in the mechanism for moving the cushion carrier part. 
     In FIGS. 3 a  and  3   b  important parts of this mechanism are shown in both the resting and the tilted-forward position. It can be seen that in the seat-back frame  11  (here shown only in outline) two tubular sections  13 ,  15  are disposed along the axes of rotation A 1 , A 2 , to one of which is welded an angled swivelling lever  17   a  and to the other, a straight swivelling lever  19   a . Both levers  17   a ,  19   a  are shown both in the (upper) resting or locked position and in the (lower) tilting-forward position. The free ends of the swivelling levers  17   a ,  19   a  are rotatably seated in abutments  21   a ,  23   a  on the cushion carrier part  5 . 
     Welded close to the end of each of the levers  17   a ,  19   a  that encloses the axis A 1 , A 2  is a pin  17   a ,  19   a , and each of the pins  17   a ,  19   a  is retained within an eye  25   a ,  25   b  in a connecting rod  25  that extends between the levers  17   a ,  19   a  and connects them to one another in such a way that a swivelling movement of one lever is necessarily transmitted to the other. (For clarity, the connecting rod  25  is shown only in the tilting-forward position of the swivelling levers.) 
     In the cross-sectional drawing of FIG. 3 b  it can be seen that the tubular section  15  bears two swivelling levers  19   a ,  19   b  arranged symmetrically with respect to a vertical midplane S 1  of the seat. In an analogous arrangement (not shown here) on the second tubular section  13  are disposed another pair of swivelling levers, of which lever  17   a  is visible in FIG. 3 a . In the upper region of FIG. 3 b  the covering cuff  7  can be seen in its folded-up state in the resting position, and in the lower region of the figure the covering cuff  7  is shown unfolded and expanded as it appears when the cushion carrier part  5  is in the position ready for tilting forward. 
     Structure and function of the mechanism shown in FIGS. 3 a  and  3   b  are additionally clarified by the perspective drawings in FIGS. 4 a  to  4   c , which show more details of the mechanism in a slightly modified embodiment. 
     In FIG. 4 a  the cushion carrier part  5  is first shown in perspective from the back. It is evident that the abutments  21   a ,  21   b  and  23   a ,  23   b  are each formed as pairs of approximately triangular projections that protrude from the back surface of the cushion carrier part  5 . Each comprises an opening (not specially numbered) through which a retention pin (not shown) can be inserted so that when the cushion carrier part  5  is set onto the swivelling levers  17   a ,  17   b  and  19   a ,  19   b , the levers are rotatably connected to the abutments  21   a ,  21   b  and  23   a ,  23   b  respectively. 
     In the vertical midplane of the cushion carrier part  5 , slightly below the abutments  23   a ,  23   b , a retaining hook is formed, which projects backward out of the back surface of the cushion carrier part  5  and serves to engage a retaining clip  29  (FIG. 4 c ), so that the cushion carrier part  5  is held firmly to the seat-back frame  11  (FIGS. 4 b  and  4   c ) in the resting position. 
     In FIGS. 4 b  and  4   c  the parts of the mechanism for moving the cushion carrier part  5  that are disposed in the seat-back frame  11  are shown. These are first, as shown in FIGS. 3 a  and  3   b  and discussed above, tubular sections  13 ,  15 , each of which is disposed substantially horizontally on an axle  14  or  16 , respectively, so as to rotate about the axes of rotation A 1 , A 2 , and upon which are mounted the swivelling levers  17   a ,  17   b  and  19   a ,  19   b  in a manner fixedly rotating therewith; also visible is a connecting rod  25 ′ (modified from the embodiment according to FIGS. 3 a  and  3   b ), which connects the levers  17   a  and  19   a  to one another. 
     It can be seen that each of the swivelling levers  17   a ,  17   b  and  19   a ,  19   b  comprises near its free end a bore to engage the above-mentioned retention pin for connection to the abutments  21   a ,  21   b  and  23   a ,  23   b , respectively, on the cushion carrier part  5 . In FIG. 4 c  it can further be seen that the axles  14 ,  16  are supported in a manner fixedly rotating therewith in bores (not specially numbered) in the seat-back frame  11  by way of corresponding bushings  14   a ,  14   b  or  16   a ,  16   b , respectively. 
     For each of the swivelling levers  19   a ,  19   b , which here are on the front surface of the tubular section  15 , there is provided a torsion spring  31   a ,  31   b  coiled coaxially around the axis of rotation A 2 . Both torsion springs  31   a ,  31   b  are fixed by one end to the seat-back frame  11  and with the other end overlap the upper edge of the associated lever  19   a  or  19   b , so as to exert a downward force on the levers. Thus when the mechanism is mounted in the seat, the torsion springs  31   a ,  31   b  simultaneously press down the cushion carrier part  5  connected to the swivelling levers, as soon as the engagement between the retaining hook  27  on the cushion carrier part  5  and the retaining clip  29  is released. 
     As can likewise be seen in FIGS. 4 b  and  4   c , in order to actuate the swivelling levers  19   a ,  19   b  and the retaining clip  29 , there are provided Bowden cables  33  and  35 , respectively. One end  33   a  of the Bowden cable  33  is inserted into a restoring lever  37 , which is disposed on the tubular section  15  and in its region opposite the end  33   a  of the Bowden cable  33 , with respect to the axis of rotation A 2 , comprises a claw  37   a  that extends under the lower edge of the swivelling lever  19   a . To fix the end  33   b  of the Bowden cable sheath  33   c  a Bowden cable holder  39  is attached to the adjacent section of the seat-back frame  11 , in which the end  33   b  of the Bowden cable sheath is suspended in a manner known per se. 
     As can be seen in FIG. 4 c , the retaining clip  29  is so mounted in its middle region that it can rotate about a vertical axis (not specially numbered) against the pretensioning or biassing force exerted by a torsion spring  30 , which in the released position acts with respect to the retaining hook  27 . At the end of the retaining clip  29  opposite the hooked section, with respect to the said vertical axis of rotation, an end  35 a of the Bowden cable  35  is suspended. (The mounting of the retaining clip  29  and the fixation of the sheath of the Bowden cable  35  to the seat-back frame are not shown in FIG. 4 c  ; however, the appropriate possibilities will be clear to those skilled in the art from the arrangement of the elements.) 
     The embodiments of a mechanism to move the cushion carrier part  5  shown in FIGS. 3 a  and  3   b  and FIGS. 4 a  to  4   c  function as follows. 
     When a force is applied that releases the tension in the Bowden cables  33  and  35 , for example by actuating the release lever  9  (FIG. 1 or  2   a  and  2   b ), one effect is that the retaining clip  29  is pivoted out of the position in which it engages the retaining hook  27  on the cushion carrier part  5 , because of the pretensioning by the torsion spring  29   a.    
     Secondly, the downward force on the swivelling levers  19   a ,  19   b  exerted by the torsion springs  31   a ,  31   b  coiled about the axis A 2  is no longer counteracted by a force exerted by the Bowden cable  33  when it is under tension and mediated by the claw  37   a  of the restoring lever  37 . 
     Because the retaining apparatus has been disengaged, and under the action of the torsion springs  31   a ,  31   b , by means of the swivelling levers  19   a ,  19   b  and the swivelling levers  17   a ,  17   b  —which are linked to the former levers by the connecting rod  25 ′ in a parallelogram-like arrangement, together forming a so-called “four-bar linkage”—the cushion carrier part  5  is pressed forward and downward with respect to the seat-back frame  11 , into the tilting-forward position shown in FIGS. 1 and 2 b.    
     Now when a pulling force is again applied to the Bowden cables  33 ,  35 , the cushion carrier part  5  is again pivoted upward and backward by means of the four-bar linkage  17   a ,  17   b ,  19   a ,  19   b . As can easily be seen in FIGS. 4 b  and  4   c , pulling on the Bowden cable  33  causes the end of the restoring lever  37  into which the end  33   a  of the Bowden cable is inserted to be pivoted downward. 
     As a result the claw  37   a  presses the swivelling lever  19   a  upward along with the elements linked to it, namely the lever  19   b , which is seated on the same tubular section  15 , and the swivelling levers  17   a ,  17   b , by way of the connecting rod  25 ′. By this means the cushion carrier part  5 , attached to the swivelling levers, is moved from the tilting-forward position back into the resting position (FIG. 2 a ). 
     It will be evident that the release or application of tension to the Bowden cables  33 ,  35 , in particular when the cushion carrier part  5  is to be returned to the locked resting position, is advantageously not quite simultaneous in the two cables. The disengagement of retaining hook  27  and retaining clip  29  precedes the lowering of the cushion carrier part  5 , and the re-engagement of these two elements occurs after the cushion carrier part  5  has been completely raised and is apposed to the headrest section of the seat back. 
     In FIGS. 5 a  and  5   b  an embodiment of the swivelling-lever mechanism that has been further modified from the preceding embodiments is sketched. The basic construction and the functional principle are the same as in the embodiments described above, so that most of the reference numerals are the same and the associated components need not be explained again. 
     This embodiment has a smaller number of individual components, which is advantageous with respect to manufacturing costs. 
     The substantial differences from the embodiments described above reside in the arrangement of the pairs of swivelling levers such that they are relatively close to one another near the midplane of the seat and each is attached to a compact component, the levers  17   a  ′,  17   b ′ being disposed on a first swivelling-lever part  17 ′ on the first axle  14  and the levers  19   a ′,  19   b ′ on a second swivelling-lever part  19 ′ on the second axle  16 . 
     Other important differences are the elimination of the connecting rod  25  or  25 ′ and the replacement of the two torsion springs  31   a ,  31   b  (according to FIGS. 4 a  to  4   c ) by a single torsion spring  31 , which acts on a special spring-action lever  41  welded to the second axle  16 . 
     The structure of the lower swivelling-lever mechanism can best be seen in FIG. 5 b . The axle  16 , shown here without the bushings  16   a ,  16   b , bears near its one end (on the left in the drawing) the torsion spring  31 , which has been pushed onto the axle  16  coaxially and with its one end is braced against the upper edge of the spring-action lever  41  while the other end—as can be seen in FIG. 5 a  and is analogous to the embodiment according to FIGS. 4 a  to  4   c —is fixed to the seat-back frame. 
     In the middle region, a bore  16 c passes radially through the axle  16 . A restoring lever  37  constructed as in the preceding embodiment is welded to a short tubular section  15 ′ and together with the latter can be pushed onto the axle  16 . Here, again, the end  33   a  of the Bowden cable  33  is fixed in a bore  37   b  in the restoring lever  37  in order to actuate the latter. Next to the tubular section  151 , on the right in the Figure, the second swivelling-lever part  191  is also pushed onto the axle  16 . This likewise comprises a radial bore  19   c ′, which is aligned with the bore  16   c  through the axle  16  so that the lower swivelling mechanism can be mounted. By insertion of a pin  43  the second swivelling-lever part  19 ′ is connected to the axle  16  in a manner fixedly rotating therewith. 
     It will be understood that the abutments on the cushion carrier part  5  must be modified from the arrangement shown in FIG. 4 a  to correspond to the changed positions of the swivelling levers on the movement mechanism. 
     FIGS. 6 a  to  6   c  show a fragmentary view of an embodiment that differs from the embodiment according to FIGS. 4 a  to  4   c  with respect to the retaining mechanism. The actual movement mechanism corresponds to that according to FIGS. 4 a  to  4   c , and its components (insofar as they have not been omitted entirely in 
     FIGS. 6 b  and  6   c  to make clearer what is shown) are identified by the same numerals as in those figures and are not explained again here. 
     The substantial alteration is that on the cushion carrier part  5  there is no retaining means; instead, this part is locked in place entirely by way of the swivelling-lever mechanism itself. The construction involved here is best seen in FIG. 6 c . Onto the tubular section  13 , which bears the angled swivelling levers  17   a ,  17   b , a first wire clamp  45  is welded, and a second wire clamp  47  is welded onto the tubular section  15 , which bears the straight swivelling levers  19   a ,  19   b . To the upper horizontal section  11   a  of the seat-back frame  11  is attached a first retaining-lever holder  49 , and to a cross-bar  11   b  of the seat-back frame  11 , near the second axis of rotation A 2 , a second retaining-lever holder  51  is attached. 
     Within each of the two retaining-lever holders  49 ,  51  is seated—by way of a torsion-spring element—a retaining lever  53  or  55 , respectively, which is so disposed and constructed as to engage with the first wire clamp  55  on the tubular section  13  or the second wire clamp  47  on the tubular section  15 . For this purpose there is provided on each retaining lever a catch section  53   a  or  55   a , respectively, that can hook into the wire clamp  45  or  47 , respectively. 
     The retaining levers  53 ,  55  each comprise an extension  53   b  or  55   b , respectively, in each of which a guide hole (not specially numbered) is provided within which a traction wire  57  is held and fixed to the retaining lever  53 ,  55  so that it cannot be pulled out. 
     When the traction wire  57  is moved in the direction of the arrow shown in its vicinity in FIG. 6 c , the retaining levers  53 ,  55  are pivoted clockwise against the spring force of their individual torsional seating elements, so that the catch section  53   a ,  55   a  of each of them is disengaged from the associated wire clamp  45 ,  47 . The swivelling-lever mechanism is thus disengaged and, as in the embodiment according to FIGS. 4 a  to  4   c , can bring about a forward rotation and lowering of the cushion carrier part  5  under the action of the torsion springs provided on the lower axle. 
     A further modified embodiment of the retaining mechanism is sketched in FIGS. 7 a  to  7   c.  Here, again, the actual swivelling mechanism corresponds to the mechanism shown in FIGS. 4 a  to  4   c  and described above, so that here again the same reference numerals are used and the corresponding components are not explained again. 
     The substantial difference from the embodiment according to FIGS. 4 a  to  4   c  and FIGS. 6 a  to  6   c  is, firstly, that a modified cushion carrier part  5 ′ is used which, in addition to the abutments  21 ,  21   b ,  23 ,  23   b  for the swivelling levers, comprises two pairs of holders  59 ,  61  for a first and a second retention pin  63 ,  65 . Corresponding to the arrangement of the retention pins  63 ,  65  on the cushion carrier part  5 ′, retaining-lever holders  67 ,  69  for retaining levers  71 ,  73  are mounted on the seat-back frame  11 , one on the upper horizontal section  11   a  and the other on the lower cross-bar  11   b.    
     In an arrangement similar to that in the embodiment according to FIGS. 6 a  to  6   c , the retaining levers  71 ,  73  are seated in the retaining-lever holders  67 ,  69  by way of torsion-spring elements and comprise hook-shaped catch sections  71   a ,  73   a  and —on the other side of the fulcrum—extending sections  71   b ,  73   b  at which the traction wire  57  acts. 
     The function of the retaining mechanism in the present arrangement to a great extent corresponds to that in the arrangement according to FIGS. 6 a  to  6   c —with the difference that the retaining levers  71 ,  73  do not engage with wire clamps on the rotatable tubular sections of the linkage mechanism, but rather hook behind the retention pins  63 ,  65  on the back surface of the cushion carrier part  5 ′, and are disengaged at these sites by movement of the traction wire in the direction of the arrow. 
     In FIGS. 8 a  to  8   c  is shown a further movement mechanism for embodying the invention, namely a combined pivot-and-slide mechanism. Another retaining mechanism is also sketched here. Insofar as the individual elements correspond to those in the embodiments described above, they are identified by the same reference numerals as above and are not described again here. 
     The arrangement comprises, firstly, a cushion carrier part  5 ″ with a headrest cushion  5   a , on the back surface of which the abutments  23   a ,  23   b  present in the previously described embodiments are again provided. In addition two pairs of holders  75   a ,  75   b  for retention pins  77   a ,  77   b  are provided, which—in contrast to the embodiment shown in FIG. 7 a —are oriented substantially vertically and are both disposed below the abutments  23   a ,  23   b . In the upper region of the cushion carrier part  5 ″ there are provided at the same level two holders  83   a ,  83   b  with guide pins  85   a ,  85   b  that point toward one another and are aligned on a common axis. 
     As can be seen in FIG. 8 b , the lower part of the movement mechanism has practically the same structure as in the embodiments described previously (cf. in particular FIG. 4 b ); here, however, the construction is illustrated by an exploded drawing. In a position corresponding to the retention pins  77   a ,  77   b  on the cushion carrier part  5 ″ there are provided on the seat-back frame (by way of holders not shown in detail here) two retaining clips  29   a ,  29   b  to engage the retention pins. These are actuated by means of Bowden cables  35   a ,  35   b.    
     On the upper side of the upper horizontal section  11   a  of the seat-back frame a guide gate  79  is mounted; it comprises two lateral guide grooves, of which only the groove  79   b  is visible in the drawings. The guide pins  85   a ,  85   b  on the cushion carrier part  5 ″ extend into these grooves and slide within them when the swivelling levers  19   a ,  19   b  pivot about the axis of rotation A, thus guiding the upper section of the cushion carrier part in a movement that corresponds to the swivelling movement of the lower section. 
     The cushion carrier part  5 ″ is locked in place and released by means of the retaining clips  29   a ,  29   b  and the retention pins  77   a ,  77   b  in basically the same way as in the embodiment according to FIGS. 4 a  to  4   c —with the difference that in the embodiment described here two retention mechanisms are provided. 
     In FIGS. 9 a  to  9   c  an embodiment of a Bowden cable actuating mechanism for the arrangements explained above is sketched. Regarding FIG. 9 a  special reference is made to the last-described embodiment of the movement mechanism, as shown in FIGS. 8 a  to  8   c.    
     FIG. 9 a , firstly, shows schematically the the entire course of the Bowden cables  33  and  35  for actuation of the restoring lever  37  and the retaining clips  29   a ,  29   b , respectively. The arrangement of the Bowden cables  33 ,  35  with respect to these components of the movement and locking mechanisms was explained above. 
     In FIG. 9 a , however, it can be seen in addition that at the upper end of the Bowden cable  35  is provided a cable extension  35   d  for connection with the retaining clip  29   b . At the ends of the Bowden cables  33 ,  35  away from the movement and retention mechanism the two cables are held together in a cable-connecting part  81 , which is set into a Bowden cable holder  83 . 
     The ends of the two Bowden cables that project beyond the cable-connecting part are fixedly joined to one another in a cable-end coupling  33 / 35   e , which is inserted into a cable-end fastening  85 . This arrangement creates a stable reference point for the actuating mechanism. 
     As can be seen in FIGS. 9 b  and  9   c , the Bowden cable-end fastening  85  containing the cable-end coupling  33 / 35   d  is attached to a fixed seat-back mounting part  87 , and the Bowden cable holder  83  containing the cable-connecting part  81  is attached to a seat-back mounting part  89  that can pivot about a seat-back axis of rotation A 3 . Both seat-back mounting parts  87 ,  89  and the hinge-sided ends and fixation elements of the Bowden cables  33 ,  34  are covered by a snap-on cap  91 . 
     In FIG. 9 c  the pivotable seat-back mounting part  89  and the hinge-sided components of the Bowden cable mechanism are shown in two different positions of the seat back, at an angle of 40° to one another. It can be seen here that when the seat back is pivoted out of the upright position into a tilted-forward position, the original tension on the Bowden cable  35  (shown here as an example) is relieved, whereas when the back is returned to the upright (resting) position, the cable is again placed under tension. 
     The result is movement of the various elements as described above, namely rotation of the retaining clips  29   a ,  29   b  about their vertical axes and of the restoring lever  37  about its horizontal axis (in each case against the pretensioning force of the associated torsion springs), and hence the disengagement and lowering, or raising and engagement of the lowerable cushion carrier part of the headrest. 
     The performance of the invention is not limited to the examples described above, but can be achieved in diverse modifications that are within the abilities of those skilled in the art. 
     In particular, a lowering of the separate part of the headrest with respect to the seat-back frame can also be accomplished by means of a pure sliding guide mechanism or in principle also by means of a simple, single-axis tilting mechanism. The sliding or folding over of the separate headrest part can be performed manually in an especially simple embodiment. 
     The disengagement can also be brought about by way of the unlocking lever of the seat back or else a separate unlocking element. Instead of attaching the actuating mechanism to the seat back or the hinge of the seat back as described above, an attachment adjacent thereto is also possible, such that the seat back or its movable hinge part acts on the adjacently disposed actuating element when the seat back is tilted forward. 
     In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.