Abstract:
The invention relates to a backrest unit for a motor vehicle seat, in particular a rear seat comprising a backrest and support connected thereto. A guide rail is arranges on the rear surface of the backrest on an x-z plane. A slide is movably mounted on the guide rail and is lockable therein in different positions. When a control device associated with the slide is actuated, it brings the slide from a normally locking position into a released position. A support comprises a near end which is hinged on the slide and a distant end which is fixable to a bodywork part.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is the U.S. National Stage of International Application No. PCT/DE2005/001950, filed Nov. 2, 2005, which claims priority to German Application No. DE 10 2005 004 271.6, filed Jan. 28, 2005 and German Application No. DE 10 2005 031 252.7, filed Jul. 5, 2005, the contents of which are expressly incorporated by reference in their entirety as part of the present disclosure. 
   BACKGROUND 
   The invention relates to a backrest of a motor vehicle seat which is particularly suited for backrests of rear seats, e.g. for a third seat row and in particular for a backrest of a seat row that is immediately adjacent a trunk. The invention relates further to a motor vehicle equipped with a seat having such a backrest. 
   A backrest of a motor vehicle seat is known in the art which has a length-variable support hinged to its backside. The backrest is reclined more or less by varying the length of this support. 
   By reclining the backrest, more or less space can be made available behind the backrest. By reclining the backrest, the seat comfort on the associated seat is also modified. As a result, a compromise must be found somehow. But generally there is the possibility to enlarge the cargo area behind the seat at the expense of the seat part and vice versa. 
   This advantage, which is given in the backrest of the type mentioned herein above, is intended to be preserved while further improving this backrest. It is the object of the invention to further develop the seat back of the type mentioned herein above so as to allow for more flexible and better adjustable adjustment, more specifically so as to allow for skillfully concealing the adjustment possibility so that it is hardly visible from the outside. 
   SUMMARY 
   This object is solved by a backrest unit of a motor vehicle seat, in particular for a back seat, with a backrest and with a carrier to which the backrest is hinge-linked, wherein a guide rail located in the x-z plane is disposed on the backside of the backrest. A slide is provided that is slidably disposed in this guide rail and is lockable in different positions in the guide rail. Further provided is an actuation device that is associated with the slide and, upon actuation, brings the slide from a normally locking position into a released or free position, and a support that has a proximate end hinged to the slide and a remote end that is configured for fixation to a carbody part. 
   The backrest is fixed in its pivotal position through the support or rather the supporting arm. At a free, unlocked backrest hinge that is also referred to as a main pivot hinge, it is further connected to a carrier or rather a carrier structure connected to the associated motor vehicle. Upon changing the position of the slide, the backrest adopts another angular position. The slide is brought into a position in which it has come free by means of the actuation device, with the slide normally being in a locked position. In this locked position, it is locked in the guide rail. The actuation device has a handle that may be disposed in immediate proximity to the slide but that is preferably located in an upper region of the backrest for ease of access. The remote end of the support is disposed on a carbody part of the associated motor vehicle. 
   Advantageously, a trunk is located behind the backrest, which is equipped in accordance with the invention. Depending on the adjustment of the support, that is to say on the recline adjustment of the backrest, the trunk gets larger and the seat space smaller and vice versa. 
   Preferably, the backrest may be pivoted onto the seat part. Accordingly, a pivot angle of about 120° is preferably possible, said pivot angle may be greater or smaller and e.g., be 90° or 160°. 
   Advantageously, the support extends substantially in the x-z plane. It may have a small component in the transverse direction, meaning in the y-direction. The support is preferably disposed on the border of the trunk so as to hardly compromise it. It is preferably located in proximity to a carbody part of the motor vehicle, for example in proximity to a wheel arch. It is also preferred that the support be covered as far as possible in order to prevent injuries. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages will become more apparent upon reviewing the appended claims and the following non restrictive description of embodiments of the invention, given by way of example only with reference to the drawing. In said drawing: 
       FIG. 1  is a schematic side view of a last seat row in a vehicle showing a wheel guard, a trunk and outlined limits of the carbody, 
       FIG. 2  is an illustration like  FIG. 1  but for the backrest which now is in a vertical position, 
       FIG. 3  is an illustration like  FIG. 1 , but for the backrest which now is completely tilted forward and for one carrier that is displaced forward; there is provided a length-variable support, 
       FIG. 4  is a perspective illustration of a guide rail in which there is located a slide, with a support hinged thereto and with a release rod, 
       FIG. 5  is the illustration of  FIG. 4 , but without the guide rail, 
       FIG. 6  is a sectional view taken along VI-VI in  FIG. 9 , meaning through the longitudinal center of the guide rail shown in  FIG. 6 , 
       FIG. 7  is a side view in the same viewing direction like in  FIG. 6 , concealed parts being shown by a discontinuous line, 
       FIG. 8  is an illustration like  FIG. 7 , but in the unlocked position, 
       FIG. 9  is a sectional view taken along the section line IX-IX in  FIG. 7 , 
       FIG. 10  is a side view of an upper region of a guide rail with an actuation device, a slide and a support, the unlocked state being shown, 
       FIG. 11  is a view like  FIG. 10  but now in the unlocked state, 
       FIG. 12  is a perspective illustration of a hinge intermediate part intermediate the backrest and the carrier structure, 
       FIG. 13  is a view like  FIG. 12 , but now in the unlocked position, 
       FIG. 14  is a perspective outside view of the hinge intermediate part of  FIG. 13 , 
       FIG. 15  is an illustration like  FIG. 14 , but now with the hinge arm being displaced, and 
       FIG. 16  is a perspective assembly drawing of a backrest arrangement with two separate backrests of different size. 
   

   DETAILED DESCRIPTION 
   The backrest unit will be explained herein after with reference to  FIG. 1 , like numerals being used throughout the figures to denote similar elements. The backrest unit of a motor vehicle seat has a backrest  20  and a carrier  22  that is normally fixed with respect to the carbody. The backrest  20  may be pivoted back and forth about a free, unlocked backrest hinge  24 , e.g. into the positions shown in the  FIGS. 2 and 3 . On the backside  26  of the backrest  20  there is disposed a guide rail  28  that extends in the x-z plane. It may also extend slightly slantways, this is to say that it may have a component in the y-direction. The guide rail  28  substantially is a C-profile rail as it may be seen for example in the  FIGS. 4 and 9 . Such type rails are also utilized for length adjustment devices of motor vehicle seats. It forms an elongate channel-shaped cavity which it defines. This cavity is open in the longitudinal direction alongside a slot that is substantially defined by the free profile ends. 
   Instead of such a profile rail, rods, any other profiles, toothed racks and the like may be used as the guide rail. 
   In the guide rail  28 , a slide  30  is slidably disposed which normally is locked in the guide rail  28 . For this purpose, the guide rail  28  has detent recesses  32  and the slide  30  has at least one locking lever  34 , in the exemplary embodiment shown it has two identically built locking levers  34 . The locking lever  34  has two detent lugs engaging into the detent recesses  32 ; see for example  FIGS. 6 and 7 . The slide  30  has a pivotal axis  36  to which the two locking levers  34  are fastened. The locking levers  34  are retained in the locking position ( FIG. 6 ) by a spring  38 . The slide  30  further has a housing  40  in which the axis  36  is retained. The housing  40  has housing ends that abut on inner corners of the substantially square inner profile of the guide rail  28  via gliding members  42  that are for example made from plastic, see for example  FIG. 9 . 
   A support  44  is hinged to the axis  36 , in the center thereof; it projects through the longitudinal slot of the guide rail  28  outward. It is implemented as a profile part, see for example the  FIGS. 4 and 5 , in order not to bend away under too heavy a load. The backrest  20  is positioned and retained through the support  44 , this also applies in case of loads exerted on the backrest in the event of an accident, so that the support  44  must be designed accordingly. If the support  44  were to bend away, the backrest  20  would no longer be held sufficiently. 
   An actuation device is provided for unlocking the slide  30 . It comprises a release rod  46 . Said rod projects as far as the upper edge of the backrest  20  where it is hinge-linked to a handgrip  48  that is also part of the actuation device. In the intervals in which there are provided the detent recesses  32 , the release rod  46  has bights  50 ,  FIG. 10  showing three such bights  50 . They are preferably arranged at intervals, just like the detent recesses  32 . They cooperate with a pin  52  that is connected to the two locking levers  34  and that protrudes transversely from them. 
     FIG. 7  shows the locked state. The pin  52  is located deep inside a bight  50 , the two locking levers  34  engage with respective detent recesses  32 . 
   If the release rod  46  is displaced, for example pulled upward pursuant to arrow  54  by means of the handgrip  48 , the pin  52  glides out of the bight  50  and comes onto an upper edge of the release rod  46 , in this position, the two locking levers  34  are raised and free from the detent recesses  32 . In this position, the backrest  20  may now be adjusted. The backrest may be pivoted slightly farther backward than shown in  FIG. 1 , namely until the slide  30  is completely at the top of the backrest  20 , but it may also be pivoted forward into the vertical position of  FIG. 2  and even further forward into the forward tilted position shown in  FIG. 3 . In said last Fig., the slide is located at the other end of the longitudinal guide forming the guide rail  28 . For any different position, detent recesses  32  may be provided according to wish. If the detent recesses  32  are arranged at intervals, it is possible to lock the backrest  20  in any graded position. 
   The support  44  has a proximate end by which it is hinge-linked to the slide  30 . It also has a remote end  56  by which it is hinge-linked to a bearing part  58 , which is again fastened to a carbody part  68 , here on a wheel guard  60 . The support  44  is located in the x-z plane. It may also have a certain component in the y direction, though. The support  44  may preferably be covered by a cover part  90 , e.g., by a carpet or a corresponding component part. It is disposed in proximity to a vehicle outboard side so as to compromise as little as possible a trunk  62  that is located behind the backrest  20 . 
   Reviewing  FIG. 1 through 3  concurrently, it appears that the support  44  may adopt various angles with respect to the guide rail  28 , the angular range being at most 180° minus twice the angle for self-locking between the materials used. In an alternative, it is also possible to form the support  44  from two parts  43 ,  45 , see  FIG. 3 , said parts being slidable with respect to each other, telescopingly guided and capable of being joined together through a suited locking device (not shown). There are many prior art possibilities for forming such type length-variable supports  44 . As also appears reviewing  FIG. 1 through 3  concurrently, the total length of the guide rail, which extends over almost the entire height of the backrest  20 , is indeed fully utilized. 
   In the exemplary embodiment shown, the detent recesses  32  are provided in the bottom of the C-shaped guide rail  28 . It is also possible to form them in the side walls or at another place. Detent projections may also be formed in the guide rail  28 , with detent windows being then provided in the locking levers  34 . 
   The handgrip  48  is disposed in a frame part in the upper region of the backrest  20  so as to be pivotal about a pivot axis  64 . The handgrip  48  is an approximately V-shaped part that is supported in the lower vertex of the V in the pivot axis  64 . If the upper part, which forms a handle, is raised, the release rod  46  is pulled upward and the lock is unlocked, see  FIG. 11 . There is provided a spring for retaining the actuation device in the locked position as shown for example in  FIG. 10 . As soon as the handgrip  48  is released, the release rod  46  glides into a position allowing for locking. A relative movement between the slide  30  and the guide rail  28  is possibly still needed, but locking is achieved in the long run. Anyway, the slide  30  has an abutment at the uppermost end of the guide rail  28  so that a tilted position of the backrest is not possible beyond a backward reclined position of the backrest  20  that is tilted a few degrees further than shown in  FIG. 1 . As a result, safety is increased in the event of rear impact collisions. 
     FIG. 16  shows a practical implementation of the backrest unit for the exemplary embodiment discussed. There are seen two backrests of a seat row, the left backrest being provided for a double seat and the right one, for a single seat. Both are adjustable independently of each other. It appears that the guide rail  28  associated with each backrest  20  is displaced as far as possible with respect to the vehicle&#39;s outboard side. For the right backrest  20 , the support  44  and the bearing part  58  can be seen. Concurrently, the guide rail  28  rigidifies the backrest  20 . 
   Herein after, the carriers, more specifically the hinge intermediate parts shown in the  FIGS. 12 through 16 , are discussed. In principle, the backrest  20  can be hinged directly to a carrier  20  fixed on the carbody. In the exemplary embodiment shown, an intermediate piece is still mounted therein between; this will be explained herein after: The carrier  22  comprises a retaining part  66  that is connected to the carbody  68 . In another implementation it is for example connected to a seat carrier. The carrier  22  further comprises a hinge intermediate part  70  that is hinge-linked to the retaining part  66  about an auxiliary pivot axis  72 . The thus formed auxiliary pivot hinge is locked through a locking device that will be discussed herein after and is normally locked. The locking device can be seen in the  FIGS. 12 through 15 . Several locking bights  74  are formed in the retaining part  66 . They cooperate with a locking bar  76  that is slidably disposed on the hinge intermediate part  70 , a long hole being formed in the hinge intermediate part  70  for guiding said locking bar. In the implementation shown, only two locking bights  74  are provided, but it is also possible to provide more locking bights. 
     FIG. 12  shows the locked state,  FIG. 13  shows the unlocked state, but still without adjustment of the hinge intermediate part  70  which is in the same position as in  FIG. 12 . There is provided a release lever  78  that is disposed on the hinge intermediate part  70  so as to be pivotal about a pivot axis. Its one arm is connected to a pull loop  80 . Any other shape of a handle is possible here. Its other arm is provided with a long hole through which a bolt  82  extends that is connected to the locking bar  76 . If the release lever  78  is pivoted, as shown in the transition between  FIG. 12  and  FIG. 13 , the locking bar  76  comes out of engagement with the rear locking bight. This state is shown in  FIG. 14 . Now, the auxiliary pivot hinge is free and may be adjusted. This occurs by the action of a user, for example by actuating the backrest  20 . If the hinge intermediate part  70  is brought into the position shown in  FIG. 15 , the upper locking position is possible and the auxiliary pivot hinge may again be locked. 
   In the holding part  66 , there is further provided a curved guide hole  84  through which a guide pin extends that is connected to the hinge intermediate part  70 . The maximum pivot angle is thus fixed. Concurrently, securement is achieved because the guide pin ends on the outside in a disk that straddles the guide hole  84 . 
   As shown in  FIG. 16 , one active intermediate part is provided for each backrest as is seen in the  FIGS. 12 through 16 . Said intermediate part is disposed on a seat side, preferably on the outboard side of the vehicle. On the other side, e.g., on the vehicle&#39;s inboard side of the backrest, there is provided a passive intermediate part. It only consists of a hinge intermediate part  70  that is solidly connected to a crossbar  86  that forms the pivot axis  64 . Accordingly, it is locked when locking occurs on the vehicle outboard side. Each back seat has its own crossbar  86  that respectively forms the pivot axis  64 . 
   In the locked position of the intermediate part described, only the upper main pivot hinge  24 , also referred to as a backrest hinge, is allowed to pivot freely. It is not until the locking device  74 ,  76  described has been released that additional pivotal movement about the auxiliary pivot axis  72  is allowed to occur. 
   The auxiliary pivot hinge described makes it possible to enlarge the volume of the trunk  62  by reducing the space in front of the backrest  20  in addition to the already described recline adjustment of the backrest  20  and vice versa. In the illustration shown in the  FIGS. 1 and 2 , the intermediate part described is in the same position as in the  FIGS. 12 through 14 . In the illustration shown in  FIG. 3 , the hinge intermediate part  70  is in the position shown in  FIG. 15 . 
   The intermediate arrangement described is principally independent of the configuration described herein above in which the backrest  20  abuts a support  44  and the other associated parts. Another variant is also possible, which is to realise the backrest hinge  24  by an adjustable and locking hinge mountings known in prior art. In this case, the angular position of the backrest is retained by the hinge mountings and not by the support  44 , the guide rail  28 , the slide  30  and so on described herein above. 
   For the configuration of the described intermediate part between backrest and a carrying structure, for example a seat carrier or a carbody, the applicant reserves the right to apply for an autonomous patent, the configuration of a support and so on only being an advantageous developed implementation that may be replaced by a prior art backrest hinge mountings or by any other fixation of the backrest. 
   The spacing between the two pivot axes of the backrest  30 , meaning of the backrest hinge  24  on the one side and the auxiliary pivot axis  72  on the other side, is about ⅙ of the total length of the backrest  20 , this spacing may range between 5 and 30% of the length of the backrest  20 . In the normal position as it is shown for example in the  FIGS. 1 and 2 , the hinge intermediate part  70  is substantially located in the same direction as the backrest  20  and actually extends as a continuation of the backrest  20 . In another consideration, it may also be considered a part of a seat carrier. In the forward tilted pivot position of the hinge intermediate part  70  as it is shown for example in  FIG. 3 , the useful length of the seat part  88  of the vehicle seat is shortened. Shortening is chosen so as to still be tolerable and the length of the hinge intermediate part  70  is selected accordingly. It is possible that the only remaining function is that of an auxiliary seat. 
   On the backrest frame of the backrest  20  as it is shown in  FIG. 16 , there may be disposed a fixation for a child seat, e.g., an Isofix fixture. Advantageously, the support  44  is embedded in the backside  26  of the backrest  20 , meaning that it protrudes as little as possible therefrom, see  FIG. 16 .