Abstract:
A vehicle is provided that includes at least one vehicle seat, which has a backrest, the inclination of which can be adjusted, and a control device, by means of which the backrest can be controlled to a lying position having a greater angle of inclination at the request of a seat user. The control device has a signal connection to a monitoring device, which detects at least one belt parameter, by means of which it can be determined whether a flawless belt course of a safety belt being worn by a seat user is ensured in the lying position.

Description:
This nonprovisional application is a continuation of International Application No. PCT/EP2011/000694, which was filed on Feb. 15, 2011, and which claims priority to German Patent Application No. DE 10 2010 010 613.5, which was filed in Germany on Mar. 8, 2010, and which are both herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a vehicle with a seat belt system and a method for tilt adjustment of a backrest of a vehicle seat. The backrest of a front passenger seat can be controlled electromotively by means of an electronic control device, by which also the backrest can be brought into different tilt positions. 
     2. Description of the Background Art 
     A generic vehicle has a front passenger seat with an electrically tilt-adjustable backrest. The backrest of the front passenger seat can be adjusted at the request of a seat occupant with the aid of an electronic control device from a normal position with a smaller tilt angle to a recumbent position with a greater tilt angle. 
     Such a tilt adjustment to the recumbent position is possible without safety problems in the case of so-called integral seats, because the associated seat belt is connected directly to the vehicle seat at least in the shoulder region of the backrest. In the case of a tilt adjustment, therefore, the connecting point located in the shoulder region is automatically pivoted concurrently, so that with a fastened seat belt a proper belt route over the seat occupant is assured in the recumbent position of the vehicle seat as well. 
     In contrast to such an integral seat, the seat belt for the front passenger seat can also be connected in the pelvic region and in the shoulder region directly on the body side to the vehicle pillar. In this case, the seat belt cannot follow a tilt adjustment of the backrest but remains unchanged. As a result, for the front passenger seat, a no longer proper belt route with a fastened seat belt results in the recumbent position. This can lead to safety problems during vehicle operation. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a vehicle with a seat belt system, in which safety problems in the recumbent position of the vehicle seat can be prevented without use of an integral seat. 
     According to an embodiment, a control device has a signal connection to a monitoring device. It can detect at least one belt parameter, which can be used to determine whether a proper belt route is assured in the recumbent position of the vehicle seat with a fastened seat belt. In the case that the monitoring device does not determine a proper belt route, suitable safety measures can therefore be brought about by the control device. 
     The invention can be used in particular in electrically adjustable vehicle seats in which the electronic control device can control the backrest electromotively. In this case, the seat occupant can select a recumbent position with a greater tilt angle, for instance, by pressing a corresponding button. Before the start of the adjusting movement to the recumbent position, the monitoring device can then detect the belt parameter used as the basis for determining whether a proper belt route can be assured in the recumbent position. 
     In determining a proper belt route, the monitoring device can generate a release signal, which is sent to the electronic control device. Only after receiving the release signal can the control device then begin or continue the adjustment actuation to the recumbent position. 
     The belt parameter detected by the monitoring device can also indicate a faulty belt route in the recumbent position. In this case, no release signal is sent to the electronic control device, so that an adjustment actuation of the backrest to the recumbent position is prevented for safety reasons. 
     The vehicle seat can be integrated as a front passenger seat in a seat belt arrangement, which includes a front seat belt and a rear seat belt. The front seat belt in this case can be a conventional three-point seat belt, for which connecting points directly to the vehicle pillar are provided in the shoulder and pelvic region. The front belt can be used in a customary manner in a normal, i.e., elevated sitting position of the front passenger seat. The rear belt can also be used at least in the recumbent position. Therefore, based on its arrangement in the rear region, a route of the shoulder belt, favorable in regard to safety, toward the back is assured, namely, depending on the set tilt of the front passenger seat. 
     The monitoring device can detect as a belt parameter a belt actuation of the rear belt or the front belt by the seat occupant of the front passenger seat. Therefore, if the electronic control device receives a request for a tilt adjustment to the recumbent position, the monitoring device will check first whether the seat occupant of the front passenger seat has or has not used the rear belt provided for this. Only when the rear belt has been used can the safety device then adjust the front passenger seat to the recumbent position. The monitoring device can therefore have at least one sensor element that detects whether the front belt or the rear belt is fastened for the seat occupant of the front passenger seat. 
     In the aforementioned safety arrangement, when the front passenger seat is in use, not only the front belt but also the rear belt of the vehicle seat disposed behind it can be used. To assure a proper belt route during use of the rear belt, the rear belt may have an adjustable belt end fitting in the vehicle longitudinal direction. This can be adjusted for use on the front passenger seat from its rear end fitting position to a front end fitting position, as a result of which a proper belt route in the pelvic region of the front passenger seat is assured. 
     The monitoring device may also have a sensor element, which can detect the end fitting of the rear belt in its front end fitting position. In an embodiment, the end fitting of the rear belt may be a belt tongue, which in each case can engage in an end fitting receptacle of the rear seat or an end fitting receptacle of the front passenger seat. In this case, the sensor element can be disposed directly in the end fitting receptacle of the front passenger seat and be made as a switch, which generates a switching signal upon insertion of the end fitting belt tongue. 
     The monitoring device may have another sensor element, which detects whether the seat occupant of the front passenger seat is buckled in. The sensor element can also be disposed as a switch in the buckle receptacle of the front passenger seat and can detect by actuation of the receptacle that the seat occupant is buckled in. 
     Moreover, for reasons of safety it should be checked whether the seat belt fastened by the front seat occupant is in fact the rear belt, to release the adjustment actuation to the recumbent position. To this end, the monitoring device may have a third sensor element, which detects whether the front belt has been actuated or not. The sensor element can detect a belt extension length of the front belt. 
     With the aforementioned first to third sensor elements, therefore, three queries can be answered, namely, first whether the rear belt with its end fitting is in the front region, secondly whether the seat occupant of the front passenger seat is buckled in, and thirdly whether the seat belt in use is in fact the rear belt and not the front belt. Only when these queries have a positive answer can the monitoring device generate the aforementioned release signal. 
     For reasons of safety, a circumstance is also important in which the rear belt is buckled in the case of when the front passenger seat is already brought into the recumbent position. It is advantageous in this case if the control device generates at least one warning signal. In addition, the control device can adjust the backrest also to a normal position with a smaller tilt angle to reduce possible safety problems. 
     In another circumstance, the seat occupant in the recumbent position of the front passenger seat may change from the rear belt to the front belt. In this case as well, the control device can produce a warning signal and/or adjust the backrest to a normal position with a smaller tilt angle. 
     One of these three queries can also be omitted if necessary. Thus, for instance, the sensor element that detects the end fitting of the rear belt in its front end fitting position can be omitted, because the seat occupant can readily detect an improper use of the end fitting belt tongue of the rear belt. 
     In addition, the end fitting belt tongue and/or the buckle belt tongue can be provided with an additional coding that can be recognized by the sensor element of the end fitting receptacle and/or buckle receptacle. In this case, the aforementioned belt unbuckling sensor could possibly be omitted. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
         FIG. 1  in a partially perspective view shows a vehicle interior with a front passenger seat and a rear row of seats disposed behind it; 
         FIG. 2  in a view according to  FIG. 1  shows the rear seat belt in its front fastening position; and 
         FIG. 3  in a view according to  FIGS. 1 and 2  shows a seat occupant of the front passenger seat with a fastened rear seat belt. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1 , in a schematic diagram a section of a vehicle interior is shown with a front passenger seat  1  and a rear row of seats  3 , of which only the right outer rear seat  5  is shown. The vehicle interior according to  FIG. 1  is bounded by a vehicle side wall  7 , which is shown only in part in the area between B-pillar  9  and C-pillar  11 . Vehicle side wall  7  at the top merges into a likewise not shown vehicle roof. 
     As is evident further from  FIG. 1 , a front belt  13  is connected to B-pillar  9 . The belt with its upper belt end is wound in a retractor  14  and with its bottom belt end fixed to a body-side end fitting, which is not shown further. A seat belt  15  is also associated with rear seat  5 . Its upper belt end is wound in a retractor  17  integrated into rear seat  5 . The bottom belt web end of rear belt  15  has an end fitting belt tongue  19 , which is described further below and is locked in place in end fitting  21  configured as a receptacle. 
     To lock rear belt  15  in its lower end fitting  21 , according to  FIG. 1 , its end fitting belt tongue  19  is inserted in end fitting receptacle  21  in a direction of movement a. In this way, a rear fastening position I, labeled in  FIG. 1  with I, is provided in which a seat occupant of rear seat  5  can fasten rear belt  15  in a known manner. 
     In fastening position I, rear seat belt  15  is guided along a side wall of the backrest of rear seat  5  downward to end fitting receptacle  21 . Another, slidably disposed buckle belt tongue  23  is provided between lower end fitting belt tongue  19  and upper retractor  17 . The tongue can be fixed removably for fastening seat belt  15  in a known manner over the seat occupant in the corresponding buckle receptacle  25 . Buckle receptacle  25  is disposed in the vehicle transverse direction on the side of vehicle seat  5 , the side opposite to the end fitting receptacle  21 . 
     As is further evident from  FIG. 1 , front passenger seat  1  at the top side of backrest  27  has a belt redirecting element  29 . It is positioned on a side facing vehicle side wall  7 . 
     Belt redirecting element  29  is configured with a laterally open guide slot  30 , in which rear seat belt  15  can be inserted, as is necessary for creating a front fastening position II, shown in  FIG. 2 , of rear seat belt  15 . 
     In order to bring rear seat belt  15  into its front fastening position II, shown in  FIG. 2 , front passenger seat  1  is assigned receptacles  31 ,  33  disposed on the side. Receptacle  31  facing vehicle wall  7  is used in this case as an end fitting receptacle, in which end fitting belt tongue  19  of rear seat belt  15  can be inserted. The belt tongue  23  slidable along the belt web can be inserted in side buckle receptacle  33 , lying opposite in the vehicle transverse direction, in order to fasten rear seat belt  15 . 
     In order to provide this second fastening position II, end fitting belt tongue  19  of rear seat belt  15  is first removed from end fitting receptacle  21 . Next, seat belt  15  is placed in redirecting element  29  and end fitting belt tongue  19  is placed removably in front end fitting  21 . The actual front seat belt  13  remains unused. 
     Additionally, in  FIG. 3 , the route of rear belt  15  is shown, when it is fastened by the seat occupant of front passenger seat  1 . It becomes evident here that seat belt  15  runs starting from the shoulder region of front passenger seat  1  approximately horizontally backward into the rear region. This horizontal route in the rear region can be retained more or less even in a tilt adjustment of backrest  27  to a recumbent position, as a result of which an optimal belt route in the shoulder area is always assured. In addition, according to  FIG. 3 , the lower end fitting of the rear seat belt  15  is also displaced in the front area, as a result of which the lower fastening point in the pelvic region also lies in such a way that there is a proper belt route in the pelvic area. 
     Provided no recumbent position of front passenger seat  5  is intended, rear seat belt  15  can again be brought into its rear fastening position I, shown in  FIG. 1 . In this case, during vehicle operation the actual front seat belt  13  can be fastened, because no tilt adjustment of backrest  27  to a recumbent position is expected. 
     Front passenger seat  1 , shown in  FIGS. 1 to 3 , can be controlled electromotively by means of an electronic control device  45  indicated in  FIG. 1 , in order to adjust the tilt of backrest  27 . To this end, electronic control device  45  has a signal connection with an indicated dc motor  47 , which during activation sets the tilt angle of backrest  27 . To this end, the seat occupant can select different tilt positions in an input unit  49 . 
     Electronic control device  45  in addition has a signal connection to a monitoring device  51 , which detects a belt parameter, with which before the start of the adjustment actuation to the recumbent position it can be determined whether presumably a proper belt route is or is not assured in a fastened seat belt. To this end, the monitoring device has sensor elements  53 ,  54 ,  55 , with which belt parameters are generated on the basis of which monitoring device  51  can determine whether the seat occupant of front passenger seat  1  has fastened front belt  13  or rear belt  15 . To this end, first sensor element  53  is disposed as a switch in the front end fitting receptacle  31 . During actuation of the front end fitting receptacle  31  by end fitting belt tongue  19  of rear belt  15 , a corresponding notification of monitoring device  51  takes place that rear belt  15  is in its front fastening position II, which is shown in  FIG. 2 . 
     The second sensor element  54  is also disposed as a switch in front buckling receptacle  33 . During an actuation of receptacle  33 , a corresponding notification of monitoring device  51  takes place, according to which at least one of seat belts  13 ,  15  has been fastened by the seat occupant of front passenger seat  1 . 
     To assure that the fastened seat belt is rear belt  15 , third sensor element  55  is provided in retractor  14  of front belt  13 . A belt extension length of retractor  14  can be determined with third sensor element  55 . If this is 0, monitoring device  51  recognizes that seat belt  13  has not been actuated. Consequently, it can be concluded that the seat belt buckled by front passenger seat occupant is rear belt  15 . If there are positive notifications from all sensor elements  53 ,  54 ,  55 , monitoring device  51  generates a release signal S free , as a result of which an adjustment actuation of front passenger seat  1  to the recumbent position is released. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.