Abstract:
A locking unit ( 10 ) for a vehicle seat ( 1 ) includes a pivotally mounted rotary latch ( 20 ) for locking to a bolt ( 12 ). The rotary latch ( 20 ) includes a rotary latch hole ( 24 ) for pivotably mounting on a bearing pin ( 51 ) which protrudes through the rotary latch hole ( 24 ). A detent ( 30 ) secures the locking unit ( 10 ) in the locked state in the event of a crash. The rotary latch ( 20 ) supports itself on a first contact point against the detent ( 30 ). The rotary latch ( 20 ) includes at least one recess area ( 25 ) which enables the rotary latch ( 20 ) to deform in the event of a crash. The recess area ( 25 ) is arranged at a distance from the rotary latch hole ( 24 ) in the radial direction.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a United States National Phase Application of International Application PCT/EP2013/060236 filed May 17, 2013 and claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2012 011 515.6 filed Jun. 1, 2012, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a locking unit for a vehicle seat with a pivotably mounted rotary latch for locking with a bolt, the rotary latch having a rotary latch hole for pivotably mounting on a bearing bolt protruding through the rotary latch hole, and a latching pawl which, in the event of a crash, secures a locked state of the locking unit by the rotary latch being supported on a first contact point on the latching pawl. The invention also relates to a vehicle seat with the locking unit. 
       BACKGROUND OF THE INVENTION 
       [0003]    DE 10 2008 051 832 A1 discloses a locking unit of the type in question for a vehicle seat. A locking unit of this type comprises a pivotably mounted rotary latch for locking with a bolt. A latching pawl which is mounted pivotably about another pivot axis secures the rotary latch in the locked state. A tensioning element which is referred to as a tolerance-compensating pawl exerts a closing moment on the rotary latch and thereby eliminates play present between the rotary latch and the bolt. 
         [0004]    DE 20 2011 100 040 U1 likewise discloses a locking unit for a vehicle seat. The rotary latch of this locking unit has a recess which differs from the circular shape and is approximately in the shape of an elongated hole and by means of which said rotary latch is mounted pivotably on a bush or a bearing bolt. 
         [0005]    The latching pawl and the tensioning element are arranged so as to be pivotable about the same axis and axially offset next to each other on a bearing bolt and interact with the rotary latch. In the event of a crash, first of all only the latching pawl secures the rotary latch by the rotary latch being supported on a contact point on the latching pawl. The crash load which is transmitted by the bolt to the rotary latch in the event of a crash is absorbed here by the contact point of the rotary latch with the latching pawl. 
         [0006]    In the event of a high crash load, the rotary latch is displaced relative to the bearing bolt along the recess which is approximately in the shape of an elongated hole until it comes to bear against the housing of the locking unit. This gives rise to a second contact point which can additionally absorb the crash load. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention is based on an object of improving a locking unit of the type mentioned at the beginning, in particular of specifying an alternative possibility for increasing the load-absorption capacity in the event of a crash, in order to increase the crash safety of a vehicle seat. 
         [0008]    A locking unit of the type in question for a vehicle seat comprises a pivotably mounted rotary latch for locking with a bolt, wherein the rotary latch has a rotary latch hole for pivotably mounting on a bearing bolt protruding through the rotary latch hole, and a latching pawl which, in the event of a crash, secures a locked state of the locking unit by the rotary latch being supported on a contact point on the latching pawl. 
         [0009]    According to the invention, it is provided that the rotary latch of the locking unit has at least one cutout region which, in the event of a crash, permits a deformation of the rotary latch, wherein the cutout region is arranged spaced apart in the radial direction from the rotary latch hole. The cutout region is therefore formed separately from the rotary latch hole and is separated therefrom, for example, by a web. 
         [0010]    Owing to the fact that the rotary latch has a cutout region which, in the event of a crash, permits a deformation, and which is arranged spaced apart in the radial direction from the rotary latch hole, the rotary latch can be displaced in the event of a crash until said rotary latch comes to bear against the housing of the locking unit, thus producing a second contact point which can additionally absorb the crash load. 
         [0011]    Owing to the deformation in the event of a crash, the rotary latch advantageously executes a displacement of this type, i.e. a translatory movement and/or a tilting movement, in order to reach the housing. 
         [0012]    According to an advantageous refinement, the cutout region is designed as a continuous opening in the axial direction. A cutout region designed in such a manner can be produced relatively simply, for example, by means of punching. 
         [0013]    According to an alternative refinement, the cutout region is designed as a notch. 
         [0014]    The rotary latch advantageously has a hook mouth for receiving the bolt. 
         [0015]    It is particularly advantageous here if the cutout region is arranged on that side of the rotary latch hole which faces away from the hook mouth. 
         [0016]    According to an advantageous development of the invention, the rotary latch has at least one load-relieving region which is provided on that side of the rotary latch hole which is opposite the cutout region. The load-relieving region assists the deformation of the rotary latch. 
         [0017]    If, in the locked state, a tensioning element exerts a closing moment on the rotary latch, a play present between the rotary latch and the bolt can thereby be eliminated. 
         [0018]    According to an advantageous refinement of the invention, the rotary latch and the latching pawl are arranged within an at least partially closed housing. 
         [0019]    The cutout region preferably runs approximately in a semicircle around the rotary latch hole. 
         [0020]    The object is also achieved by a vehicle seat comprising at least one locking unit according to the invention. 
         [0021]    The invention is explained in more detail below with reference to an advantageous exemplary embodiment illustrated in the drawings. However, the invention is not restricted to said exemplary embodiment. 
         [0022]    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 
         [0023]    In the drawings: 
           [0024]      FIG. 1  is an exploded illustration of a locking unit; 
           [0025]      FIG. 2  is a schematized illustration of a vehicle seat; 
           [0026]      FIG. 3  is a top view of parts of the locking unit according to a first exemplary embodiment in the locked state; 
           [0027]      FIG. 4  is a top view of parts of the locking unit according to the first exemplary embodiment in the event of a crash; and 
           [0028]      FIG. 5  is a top view of parts of the locking unit according to a second exemplary embodiment in the locked state. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    Referring to the drawings in particular, in a motor vehicle, a locking unit  10  for connecting a backrest  3  of a vehicle seat  1 , in particular a rear seat, to a vehicle structure is provided. The backrest  3  here is attached to a seat part  5  so as to be pivotable from a use position into a not-in-use position. 
         [0030]    However, the locking unit  10  can also be used at different locations, for example for fastening the seat part  5  of the vehicle seat  1  to the floor structure of the motor vehicle, or in a door lock. 
         [0031]    The arrangement of the vehicle seat  1  within the vehicle and the customary direction of travel thereof define the directional details used below. A direction oriented perpendicularly to the ground is referred to below as the vertical direction and a direction perpendicular to the vertical direction and perpendicular to the direction of travel is referred to below as the transverse direction. 
         [0032]    The locking unit  10  has a lock housing which comprises a first side plate  16  and a second side plate  18 . In the present case, the basic surfaces of the side plates  16 ,  18  are of flat configuration and are arranged in a plane defined by the direction of travel and the vertical direction, i.e. perpendicularly to the transverse direction. Each of the side plates  16 ,  18  comprises two bearing bores  13  which, in the present case, are of circular design. 
         [0033]    The first side plate  16  and the second side plate  18  form a receptacle which opens in the direction of a bolt  12  in order to receive the latter for locking purposes. The locking unit  10  in the present case is fastened to the backrest  3  and the bolt  12  is fastened to the vehicle structure. It is also conceivable for the locking unit  10  to be fastened to the vehicle structure and for the bolt  12  to be fastened to the backrest  3 . That portion of the bolt  12  which is to be received by the receptacle generally runs horizontally in the transverse direction. 
         [0034]    A rotary latch  20  is mounted pivotably on a first bearing bolt  51  which, in turn, is fastened to the first side plate  16  and to the second side plate  18 . For this purpose, the rotary latch  20  has a rotary latch hole  24  through which the first bearing bolt  51  protrudes. The rotary latch  20  furthermore has a hook mouth  21  for interaction with the bolt  12 . The rotary latch  20  is pretensioned in the opening direction by means of a first spring  71 . 
         [0035]    The rotary latch  20  has a functional surface  22  which partially laterally bounds the hook mouth  21 . In the locked state, the functional surface  22  approximately faces in the direction of a second bearing bolt  52  which is arranged parallel to the first bearing bolt  51  and therefore likewise runs in the transverse direction. In the present case, the functional surface  22  is of planar design, but can also be, for example, curved in the shape of an arc of a circle and of concave design. 
         [0036]    On that side of the hook mouth  21  which faces away from the rotary latch hole  24  and is opposite the functional surface  22 , the hook mouth  21  is bounded laterally by a lug  28  of the rotary latch  20 . 
         [0037]    The rotary latch  20  has a basic body which is bounded in the axial direction by a flat basic surface in each case. The width of the functional surface  22  corresponds to the thickness of the basic body of the rotary latch  20 , i.e. to the extent of the basic body in the axial direction. 
         [0038]    The first bearing bolt  51  is inserted into respective bearing bores  13  in the side plates  16 ,  18  and protrudes perpendicularly from the basic surfaces of the side plates  16 ,  18 . The first bearing bolt  51  therefore runs horizontally in the transverse direction. In the present case, the preferably metallic first bearing bolt  51  is riveted or calked to the side plates  16 ,  18 . The first bearing bolt  51  is preferably designed in the form of a hollow cylinder in order to receive a fastening means, for example a screw, by means of which the locking unit  10  is fastened to the backrest  3  during the installation. 
         [0039]    The second bearing bolt  52  is also inserted into respective bearing bores  13  in the side plates  16 ,  18  and protrudes perpendicularly from the basic surfaces of the side plates  16 ,  18 . The second bearing bolt  52  therefore likewise runs horizontally in the transverse direction. In the present case, the preferably metallic second bearing bolt  52  is riveted or calked to the side plates  16 ,  18 . In the same manner as the first bearing bolt  51 , the second bearing bolt  52  is preferably designed in the form of a hollow cylinder in order to receive a fastening means, for example a screw, by means of which the locking unit  10  is fastened to the backrest  3  during the installation. 
         [0040]    A tensioning element  40  is mounted pivotably on the second bearing bolt  52 . For this purpose, the tensioning element  40  has a tensioning element hole  44  which, in the present case, is circular and is penetrated by the second bearing bolt  52 . The tensioning element  40  is pretensioned toward the rotary latch  20  by means of a third spring  73 . 
         [0041]    In the locked state, when the hook mouth  21  of the rotary latch  20  receives the bolt  12 , the tensioning element  40  exerts a closing moment on the rotary latch  20  owing to the pretensioning by the third spring  73  as a securing element. For this purpose, the tensioning element  40  has a tensioning surface  41  which is curved eccentrically with respect to the second bearing bolt  52  and is in non-self-locking contact with the functional surface  22  of the rotary latch  20 . In the present case, the tensioning surface  41  is curved in the shape of an arc of a circle and is of convex design. 
         [0042]    A latching pawl  30  is arranged on the second bearing bolt  52  axially next to the tensioning element  40  and is likewise mounted pivotably on the second bearing bolt  52 , i.e. in alignment with the tensioning element  40 . For this purpose, the latching pawl  30  has a latching pawl hole  34  which, in the present case, is circular and is penetrated by the second bearing bolt  52 . The latching pawl  30  is pretensioned toward the rotary latch  20  by means of a second spring  72 . 
         [0043]    In the present case, the latching pawl  30  is arranged adjacent to the first side plate  16  and, in the present case, the tensioning element  40  is arranged adjacent to the second side plate  18 . The latching pawl  30  and the tensioning element  40  are coupled by empty travel for carrying-along purposes, for example by means of a slot and pin guide or by means of an axially protruding driver. 
         [0044]    The latching pawl  30  has a latching surface  31  which is in the vicinity of the tensioning surface  41  of the tensioning element  40 . In the locked state, the latching surface  31  is positioned spaced apart from the functional surface  22  of the rotary latch  20 . In the present case, the latching surface  31  is curved in the shape of an arc of a circle and is of convex design, but may also be planar. 
         [0045]    The width of the functional surface  22 , which corresponds to the thickness of the basic body of the rotary latch  20 , also approximately corresponds to the total of the thickness of the latching pawl  30  and the thickness of the tensioning element  40 . The rotary latch  20  therefore has approximately the same material thickness as the latching pawl  30  and the tensioning element  25  together. 
         [0046]    According to a first exemplary embodiment, the rotary latch  20  has a cutout region  25  on that side of the rotary latch hole  24  which faces away from the hook mouth  21 . In the present case, the cutout region  25  is designed as a continuous opening in the axial direction and runs approximately in a semicircle around the rotary latch hole  24 . The cutout region  25  therefore completely penetrates the basic body of the rotary latch  20  in the axial direction, parallel to the rotary latch hole  24  which, in the present case, is designed as a circular bore. 
         [0047]    The cutout region  25  here is arranged spaced apart in the radial direction from the rotary latch hole  24 . The cutout region  25  is therefore formed separately from the rotary latch hole  24  and, in the present case, is separated therefrom by a web. The cutout region  25  therefore does not have any connection with the rotary latch hole  24 . 
         [0048]    However, the cutout region  25  may also be designed in a different manner. For example, the cutout region  25  can be designed as a notch which extends from the surface of the basic body of the rotary latch  20  into the basic body, but not through the latter. The semicircular cutout region  25  can also be interrupted by one or more webs. Furthermore, the cutout region  25  can have a design differing from the semicircular shape, for example a rectangular, circular or oval shape. Similarly, a plurality of rectangular, circular, oval or differently designed cutout regions  25  can be provided next to one another and/or separated from one another by webs. 
         [0049]    In the present case, two load-relieving regions  27  are provided on that side of the rotary latch hole  24  which is opposite the cutout region  25 . The load-relieving regions  27  are therefore arranged approximately between the rotary latch hole  24  and the hook mouth  21  of the rotary latch  20 . In the present case, the load-relieving regions  27  are formed in the shape of a segment of a circle and are separated from one another by a web running in the radial direction. In the present case, the load-relieving regions  27  are likewise designed as a continuous opening in the axial direction and completely penetrate the basic body of the rotary latch  20  in the axial direction, parallel to the rotary latch hole  24 . 
         [0050]    The load-relieving regions  27  can also be designed so as to differ from the shape shown here, for example can be designed as a notch or with a different design, in a similar manner to the cutout region. It is also conceivable for only one load-relieving region  27  to be provided or for the latter also to be entirely omitted. 
         [0051]    According to a second exemplary embodiment, which is illustrated in  FIG. 5 , there is no load-relieving region. 
         [0052]      FIG. 3  illustrates the positions of the rotary latch  20  and the latching pawl  30  of the locking unit  10  according to the first exemplary embodiment in the locked state. 
         [0053]    The bolt  12  bears against the lug  28  of the rotary latch  20  in the hook mouth  21 . In the event of a crash, the rotary latch  20  experiences an opening moment by means of the bolt  12  and pushes the tensioning element  40  (not illustrated here) away. As a result, the latching surface  31  of the latching pawl  30  first of all enters into contact with the functional surface  22  of the rotary latch  20 . The latching pawl  30  thus serves to support the rotary latch  20  and, as a securing element, prevents a further rotation of the rotary latch  20  in the opening direction. The latching pawl  30  therefore prevents the rotary latch  20  from opening. 
         [0054]    If, on account of the crash, the bolt  12  exerts a further load on the lug  28  of the rotary latch  20 , the rotary latch  20  undergoes a translatory movement approximately in the loading direction. In the process, the bearing bolt  51  (not illustrated in  FIG. 3 ), on the side facing away from the hook mouth  21  presses against the wall of the rotary latch hole  24 . In the process, the cutout region  25  of the rotary latch  20  is compressed and the rotary latch  20  is deformed. The rotary latch  20  migrates here in the loading direction mentioned. 
         [0055]    The movement of the rotary latch  20  in the loading direction ends when the rotary latch  20  enters into contact with one of the housing parts  16 ,  18  or when the rotary latch has covered a distance which corresponds to the radial extent of the cutout region  25 . This position is illustrated in  FIG. 4 . 
         [0056]    During the movement described here of the rotary latch  20 , the load-relieving regions  27  also assist the deformation of the rotary latch  20 . The load-relieving regions  27  are expanded here, as a result of which the radial extent thereof is increased. The material of the rotary latch  20  in the region between the load-relieving regions  27  and the rotary latch hole  24  can also tear off in the process, as can the web between the load-relieving regions  27 . 
         [0057]    In all of the exemplary embodiments described here, the first bearing bolt  51 , as illustrated in  FIG. 1 , is encased by a first slide bush  61 . The first slide bush  61  is also designed in the form of a hollow cylinder. The first slide bush  61  is therefore located in the radial direction between the first bearing bolt  51  and the rotary latch  20 . 
         [0058]    As illustrated in  FIG. 1 , the second bearing bolt  52  is encased by a second slide bush  62 . The second slide bush  62  is also designed in the form of a hollow cylinder. The second slide bush  62  is therefore located in the radial direction between the first bearing bolt  51  and the latching pawl  30  and also the tensioning element  40 . 
         [0059]    The first sliding bush  61  and the second sliding bush  62  can also be omitted or formed integrally with the first bearing bolt  51  and the second bearing bolt  52 . 
         [0060]    In the locked state of the locking unit  10 , the bolt  12  is located in the receptacle formed by the side plates  16 ,  18  and in the hook mouth  21  of the closed rotary latch  20 . The tensioning element  40  secures the rotary latch  20  by interaction of the tensioning surface  41  with the cam  26 . The latching surface  31  of the latching pawl  30  is slightly spaced apart from the functional surface  22  of the rotary latch  20 . 
         [0061]    In order to open the locking unit  10 , the latching pawl  30  is pivoted away from the rotary latch  20 , as a result of which the latching surface  31  of the latching pawl  30  is further away from the functional surface  22  of the rotary latch  20 . The latching pawl  30  carries along the tensioning element  40  owing to the carrying-along coupling, and therefore the rotary latch  20  is no longer secured. 
         [0062]    By means of the pretensioning on account of the first spring  71 , the rotary latch  20  opens, i.e. pivots in the opening direction. Alternatively or in addition to the pretensioning by the first spring  71 , the rotary latch  20  can also be carried along for opening purposes by the latching pawl  30  or by the tensioning element  40 . 
         [0063]    Owing to the pivoting movement of the rotary latch  20 , the hook mouth  21  draws back from the receptacle formed by the side plates  16 ,  18  and releases the bolt  12  which moves away from the locking unit  10  counter to the pivoting-in direction. If the bolt  12  has left the hook mouth  12 , the locking unit  10  is in the unlocked state. 
         [0064]    If, in said unlocked state, the bolt  12  passes again into the receptacle formed by the side plates  16 ,  18  and enters into contact with the border of the hook mouth  21 , the bolt  12  pushes the rotary latch  20  into the closed position thereof. The tensioning element  40 , owing to the pretensioning thereof by the third spring  73 , moves along the cam  26 . Carried along by the tensioning element  40  or owing to the pretensioning by the second spring  72 , the latching pawl  30  pivots toward the rotary latch  20 , with the latching surface  31  approaching the functional surface  22  of the rotary latch  20 . The locking unit  10  is then in the locked state again. 
         [0065]    The features disclosed in the above description, the claims and the drawings can be of importance both individually and in combination for realizing the invention in the various configurations thereof. 
         [0066]    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.