Abstract:
A locking device ( 10 ) for a vehicle seat includes a detent ( 13 ) for securing a rotary latch ( 11 ) and a light source ( 41 ). When the locking device ( 10 ) is completely locked, a light beam emitted from the light source ( 41 ) penetrates the locking device ( 10 ) in the axial direction.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a United States National Phase Application of International Application PCT/EP2013/071721 filed Oct. 17, 2013 and claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2012 023 685.9 filed Nov. 28, 2012, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a locking device for a vehicle seat, comprising a latching pawl for securing a rotary catch, and a light source. The invention also relates to an arrangement of at least two locking devices and to a vehicle seat having the features of claim  1  the arrangement of at least two locking devices. 
       BACKGROUND OF THE INVENTION 
       [0003]    A locking device of the generic type for a vehicle seat is known from DE 10 2008 051 832 A1. A locking device of this type comprises a pivotably mounted rotary catch for locking to a pin. A latching pawl which is pivotably mounted about another pivot axis secures the rotary catch in the locked state. A tolerance compensation pawl exerts a closing torque on the rotary catch and in this way eliminates play which exists between the rotary catch and the pin. 
         [0004]    The latching pawl and the tolerance compensation pawl are arranged on a bearing pin such that they can be pivoted about the same pivot axis, offset axially next to one another, and interact with the rotary catch. In the case of a crash, only the latching pawl secures the rotary catch, by the rotary catch being supported at a contact point on the latching pawl. The crash load which the pin transmits to the rotary catch in the case of a crash is absorbed here by the contact point of the rotary catch with the latching pawl. 
         [0005]    If the locking device is locked, the rotary catch is situated in the locked position, said rotary catch engaging around the pin, and the latching pawl is situated in the securing position, said latching pawl securing the rotary catch. If the locking device is unlocked, the rotary catch is situated in the unlocked position, said rotary catch releasing the pin, and the latching pawl is situated in the release position, said latching pawl releasing the rotary catch. 
         [0006]    It is extremely important for a user of the vehicle seat that all the locking devices of the vehicle seat are completely locked. If a locking device is unlocked, the vehicle seat can become detached from the vehicle structure during a crash, which can lead to injuries of the user. It is also a problem if a locking device is only partially locked; although the rotary catch receives the pin, the latching pawl is not situated in the securing position. The rotary catch is also not secured in this case and can open the locking device in the case of a crash. 
         [0007]    DE 102 30 637 A1 has disclosed a locking device for a vehicle seat, which locking device permits a visual display of the locking state. If the locking device is not locked, a light source transmits a light beam via a light guide to a light outlet point, where the non-locked state is displayed visually. If the locking device is locked, the light beam which is transmitted by the light source is interrupted and therefore does not reach the light outlet point. The interruption of the light beam takes place by means of a linearly displaceable slide. Here, the slide is coupled via a lever mechanism to a latching pawl which is called a detent, is mounted pivotably and secures a rotary catch if the locking device is locked. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention is based on an object of improving a locking device for a vehicle seat of the type mentioned at the outset, in particular of making a display of the locking state of the locking device or a plurality of locking devices possible and of simplifying the construction of the locking device, and of providing a corresponding vehicle seat. 
         [0009]    According to the invention, a locking device of a generic type for a vehicle seat comprises a latching pawl for securing a rotary catch, and a light source. The locking device is provided according to the invention that, if the locking device is completely locked, a light beam which is emitted by the light source penetrates the locking device in the axial direction. 
         [0010]    This arrangement makes a comparatively simple structural construction of the locking device possible. Elements which already exist in the locking device, in particular the rotary catch or the latching pawl, can allow the light beam to pass or can interrupt it depending on their position if the locking device is locked or unlocked. An additional mechanism for interrupting the light beam is therefore not required. 
         [0011]    If the locking device is unlocked, and advantageously also if the locking device is only partially locked, the light beam which is emitted by the light source is interrupted within the locking device by an element which is already present in the locking device. A visual determination of the locking state of the locking device is therefore possible. 
         [0012]    According to one advantageous refinement of the invention, the latching pawl assumes the function of interrupting the light beam. 
         [0013]    To this end, the latching pawl has a passage opening which the light beam which is emitted by the light source penetrates if the locking device is completely locked. 
         [0014]    If the locking device is unlocked, the light beam which is emitted by the light source strikes the latching pawl and is therefore interrupted by the latching pawl. 
         [0015]    The latching pawl is preferably arranged within a housing which comprises a first housing part and a second housing part. 
         [0016]    According to one advantageous development of the invention, a first passage opening is provided in the first housing part and a second passage opening is provided in the second housing part. If the locking device is completely locked, the light beam which is emitted by the light source penetrates the first passage opening and the second passage opening. 
         [0017]    If the locking device is completely locked, a center of the third passage opening which is provided in the latching pawl lies on a throughway line which is defined by a center of the first passage opening and a center of the second passage opening. The light beam can therefore penetrate the housing of the locking device in a rectilinear manner. 
         [0018]    Here, the throughway line advantageously runs in the axial direction. 
         [0019]    The passage openings in the housing parts and in the latching pawl can be manufactured comparatively simply if the first passage opening and/or the second passage opening and/or the third passage opening are/is configured as a circular hole. 
         [0020]    The construction of the locking device is particularly compact if the light source is fastened directly to the first housing part or to the second housing part. 
         [0021]    In one simple refinement, the light source comprises only a fiber optic cable. 
         [0022]    If the light source comprises a mirror, the light beam can be diverted, in particular from a direction which runs perpendicularly with respect to the axial direction into the axial direction. 
         [0023]    A light receiver is advantageously provided which is struck by the light beam which is emitted by the light source if the locking device is completely locked. 
         [0024]    In one simple refinement, the light receiver comprises only a fiber optic cable. 
         [0025]    If the light receiver comprises a mirror, the light beam can be diverted, in particular from the axial direction into a direction which runs perpendicularly with respect thereto. 
         [0026]    The object is also achieved by way of an arrangement of at least two locking devices according to the invention, the light receiver of the first locking device being connected by means of a fiber optic cable to the light source of the second locking device. This allows a visual test as to whether both locking devices are completely locked. 
         [0027]    The object is also achieved by way of a vehicle seat, which vehicle seat comprises at least one locking device according to the invention. 
         [0028]    The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    In the drawings: 
           [0030]      FIG. 1  is a cross section through a locking device in the completely locked state; 
           [0031]      FIG. 2  is a longitudinal section through the locking device from  FIG. 1  in the completely locked state; 
           [0032]      FIG. 3  is a cross section through a locking device in the partially locked state; 
           [0033]      FIG. 4  is a longitudinal section through the locking device from  FIG. 3  in the partially locked state; and 
           [0034]      FIG. 5  is an arrangement for displaying the locking state of a plurality of locking devices. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0035]    A vehicle seat (not shown) can be fastened to a vehicle structure by means of a plurality of locking devices  10 . Here, two locking devices  10  are provided in a rear region (in the driving direction) of the vehicle seat, in each case one of said locking devices  10  being arranged on the right in the driving direction and the other of said locking devices  10  being arranged on the left in the driving direction. Two further locking devices  10  are likewise provided in a front region (in the driving direction) of the vehicle seat, in each case one of said locking devices  10  being arranged on the right in the driving direction and the other of said locking devices  10  being arranged on the left in the driving direction. 
         [0036]    In the completely locked state, a rotary catch  11  of the locking device  10  engages around a pin which is arranged on the vehicle structure. In the unlocked state of the locking device  10 , the rotary catch  11  is pivoted about a first pivot axis  71  and releases the pin. For unlocking, an unlocking lever  16  which is provided on a latching pawl  13  is pivoted about a second pivot axis  72 , as a result of which the latching pawl  13  pivots away from the rotary catch  11  and releases the latter. A locking device  10  of this type is described, for example, in DE 10 2008 051 832 A1, the disclosure of which in this regard is expressly incorporated. 
         [0037]    The first pivot axis  71  and the second pivot axis  72  run parallel to one another in a direction which will be called the axial direction in the following text. The pin which is arranged on the vehicle structure also runs in the axial direction in the present case. 
         [0038]    A tolerance compensation pawl which is likewise mounted such that it can be pivoted about the second pivot axis  72  is provided to compensate for manufacturing tolerances. 
         [0039]    The rotary catch  11 , the latching pawl  13  and further components of the locking device  10  are arranged within a housing which comprises a first housing part  21  and a second housing part  22  in the present case. One of the two housing parts  21 ,  22  (the second housing part  22  in the present case) is connected to a structural part  5  of the vehicle seat here. The housing parts  21 ,  22  largely accommodate the remaining components of the locking device  10  between them. 
         [0040]    The housing parts  21 ,  22  are of approximately flat configuration and define planes which lie offset in parallel to one another and run perpendicularly with respect to the pivot axes  71 ,  72 . 
         [0041]    A first passage opening  31  is provided in the first housing part  21 . A second passage opening  32  is provided in the second housing part  22 . A third passage opening  33  is provided in the latching pawl  13 . In the present case, the passage openings  31 ,  32 ,  33  are configured as circular holes. 
         [0042]    The center of the first passage opening  31  and the center of the second passage opening  32  define a throughway line  75  which lies parallel to the pivot axes  71 ,  72  and runs in the axial direction. The third passage opening  33  is arranged in such a way that, in the completely locked state of the locking device  10  when the latching pawl  13  secures the rotary catch  11 , its center also lies on the throughway line  75 , that is to say is aligned with the center of the first passage opening  31  and the center of the second passage opening  32 . 
         [0043]    A light source  41  is arranged outside the housing of the locking device  10 , in the vicinity of the first passage opening  31 . In the present case, the light source  41  is fastened to the first housing part  21 , on the side which faces away from the second housing part  22 . 
         [0044]    A light receiver  42  is arranged outside the housing of the locking device  10 , in the vicinity of the second passage opening  32 . In the present case, the light receiver  42  is fastened to the structural part  5  of the vehicle seat, on the side which faces away from the first housing part  21 . A fourth passage opening  34  is provided in the structural part  5  of the vehicle seat, which fourth passage opening  34  is likewise configured as a circular hole and the center of which lies on the throughway line  75 . It is also conceivable that the light receiver  42  is fastened to the second housing part  22 , on the side which faces away from the first housing part  21 . 
         [0045]    The locking device  10  is completely locked in the illustrations according to  FIG. 1  and  FIG. 2 . The latching pawl  13  secures the rotary catch  11  and the third passage opening  33  therefore lies on the throughway line  75 . A light beam which is emitted by the light source  41  runs in the axial direction through the first passage opening  31 , through the third passage opening  33 , through the second passage opening  32  and through the fourth passage opening  34  and strikes the light receiver  42 . 
         [0046]    The locking device  10  is partially locked in the illustrations according to  FIG. 3  and  FIG. 4 . The latching pawl  13  is pivoted away from the rotary catch  11  and does not secure the latter. The third passage opening  33  therefore lies away from the throughway line  75 . A light beam which is emitted by the light source  41  passes through the first passage opening  31  and then strikes the latching pawl  13 . In the present case, the latching pawl  13  is composed of metal and is opaque. The light beam is therefore interrupted and does not strike the light receiver  42 . 
         [0047]    It is also conceivable that the latching pawl  13  does not have a passage opening. In this case, the first passage opening  31 , the second passage opening  32  and the fourth passage opening  34  are arranged in such a way that, if the locking device  10  is completely locked, the light beam which is emitted by the light source  41  runs in the axial direction through the first passage opening  31 , past the unlocking lever  16  or another part of the latching pawl  13 , through the second passage opening  32  and through the fourth passage opening  34  and strikes the light receiver  42 . If the locking device  10  is partially locked and if the locking device  10  is not locked, the light beam which is emitted by the light source  41  strikes the unlocking lever  16  or another part of the latching pawl  13 , is interrupted there and does not strike the light receiver  42 . 
         [0048]    The locking state of the locking device  10  can therefore be determined by way of an evaluation of a signal of the light receiver  42 . If the light beam which is emitted by the light source  41  strikes the light receiver  42 , the locking device  10  is completely locked. If the light beam which is emitted by the light source  41  does not strike the light receiver  42 , the locking device  10  is not completely locked, that is to say is partially locked or unlocked. 
         [0049]    The light source  41  can be configured as an active illumination unit  44 , for example as shown in  FIG. 5 , in the form of an LED. The light source  41  can also be configured, for example as in the present case, as a passive transmitting unit  46 . In the present case, the transmitting unit  46  comprises in each case one fiber optic cable  48  which transports light which is generated by an external illumination device to the respective transmitting unit  46 , and a mirror  50  which diverts the incoming light in the form of a light beam in the axial direction on to the first passage opening  31 . 
         [0050]    It is also conceivable that the abovementioned mirror is dispensed with, the transmitting unit  46  comprising, for example, a fiber optic cable  48  which is arranged in such a way that a light beam which emerges from the fiber optic cable  48  strikes the first passage opening  31  in the axial direction. 
         [0051]    The light receiver  42  can be configured as a light-sensitive sensor, for example in the form of a photodiode. The light receiver  42  can also be configured, for example as in the present case, as a receiving unit  47 . In the present case, the receiving unit  47  comprises a fiber optic cable  48  and a mirror  50  which diverts a light beam coming from the axial direction in the direction of the fiber optic cable  48 . 
         [0052]    It is also conceivable that the abovementioned mirror is dispensed with, the receiving unit  47  comprising, for example, a fiber optic cable  48  which is arranged in such a way that a light beam coming from the axial direction strikes the fiber optic cable  48 . 
         [0053]    The exemplary embodiment which is shown in  FIG. 5  comprises an arrangement for displaying the locking state of two locking devices  10 . In the illustration which is shown here, both locking devices  10  are completely locked. 
         [0054]    The locking device  10  which is arranged on the right-hand side in the illustration which is shown comprises an illumination unit  44  in the form of an LED as light source  41  and a light receiver  42  which is configured as a receiving unit  47 . 
         [0055]    The locking device  10  which is arranged on the left-hand side in the illustration which is shown comprises a transmitting unit  46  as light source  41  and a light receiver  42  which is configured as a receiving unit  47 . 
         [0056]    By means of a first fiber optic cable  48 , the receiving unit  47  of the locking device  10  which is arranged on the right-hand side is connected to the transmitting unit  46  of the locking device  10  which is arranged on the left-hand side. By means of a second fiber optic cable  48 , the receiving unit  27  of the locking device  10  which is arranged on the left-hand side is connected to a display device  60 . 
         [0057]    In the present case, if both locking devices  10  are completely locked, the illumination unit  44  generates a light beam which strikes the receiving unit  47  of the locking device  10  which is arranged on the right-hand side. From there, the light beam is transmitted via the first fiber optic cable  48  to the transmitting unit  46  of the locking device  10  which is arranged on the left-hand side. From there, the light beam passes to the receiving unit  47  of the locking device  10  which is arranged on the left-hand side. From there, the light beam is transmitted via the second fiber optic cable  48  to the display device  60  which is arranged on a dashboard of the vehicle in the present case. 
         [0058]    If the display device  60  is therefore lit, both locking devices  10  of the vehicle seat are completely locked. If one of the two locking devices  10  is not locked, its latching pawl  13  interrupts the light beam which runs in the axial direction and no light therefore arrives at the display device  60 . If the display device  60  is therefore not lit, at least one of the two locking devices  10  of the vehicle seat is not completely locked. 
         [0059]    Instead of the transmission of the light beam by means of fiber optic cables  48 , it is also conceivable to convert the light beam which can be considered to be a visual signal into an electrical signal by means of a light receiver  42  which is configured as a photodiode and to transmit said electrical signal. 
         [0060]    The electrical signal which is converted in this way and indicates the complete locking of the associated locking device  10  can then be transmitted via electrical lines to the dashboard or to a bus system of the vehicle. 
         [0061]    If a locking device  10  is not completely locked, a visual display can take place in the dashboard. A haptic indication is likewise conceivable, for example by way of the generation of a vibration in the vehicle seat. 
         [0062]    The features which are disclosed in the above description, the claims and the drawings can be of significance both individually and in combination for the implementing of the invention in its various refinements. 
         [0063]    While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.