Abstract:
A vehicle seat locking unit ( 10 ) includes a lock housing having a receptacle opening ( 19 ) for receiving a locking bolt ( 12 ). A rotary latch ( 20 ) is mounted to swivel around a bearing bolt ( 51 ) and has a hook aperture ( 21 ) for locking together with the locking bolt. The bearing bolt is aligned in an axial direction and the receptacle opening is delimited by a locking bolt stop element ( 61 ), located in the hook aperture, which axially protrudes into the lock housing. In a locked state the locking bolt extends in the axial direction. A first contact region ( 71 ), between the locking bolt and the stop element, and a second contact region ( 72 ), between the locking bolt and the rotary latch, partially overlap in the axial direction, or the first contact region lies completely within the second contact region in the axial direction. A vehicle seat ( 1 ) includes such locking unit.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a United States National Phase Application of International Application PCT/EP2014/067222 filed Aug. 12, 2014 and claims the benefit of priority under 35 U.S.C. §119 of German Patent Application 10 2013 216 054.2 filed Aug. 14, 2013 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 including a lock housing with a receiving opening for receiving a locking bolt, as well as a rotary latch which is mounted so as to be pivotable about a first bearing bolt and comprises a hook aperture for locking with the locking bolt, wherein the bearing bolt is aligned in an axial direction, and the receiving opening is defined by a stop element, the stop element providing a stop for the locking bolt which is situated in the hook aperture, and the stop element projecting into the lock housing in the axial direction. The invention also relates to a vehicle seat including the locking unit. 
       BACKGROUND OF THE INVENTION 
       [0003]    DE 10 2008 033 304 A1 discloses a vehicle seat with a locking unit. The locking unit, in this case, is fastened on a structural part, in particular a backrest, of the vehicle seat and serves for locking the backrest to a structure of the vehicle, or to the bodywork thereof. To this end, the locking unit comprises a rotary latch which is designated as a pawl and, in the locked state of the locking unit, encompasses a locking bolt which is fastened to the structure of the vehicle. 
         [0004]    DE 103 04 574 B4 discloses a locking unit for a vehicle seat. A locking unit of this type includes a pivotably mounted rotary latch for locking with a locking bolt. A latching pawl, which is mounted so as to be pivotable about a different pivot axis, secures the rotary latch in the locked state. A tensioning element exerts a closing torque onto the rotary latch and in this way eliminates any play present between the rotary latch and the locking bolt. 
         [0005]    DE 101 26 687 A1 discloses a generic locking unit with a stop element, which defines a receiving opening of a lock housing, and a rotary latch with an extensively constant thickness. In a locked state of the locking unit and with a locking bolt which extends precisely in the axial direction, a first contact region between the locking bolt and the stop element is arranged in the axial direction next to a second contact region between the locking bolt and the rotary latch. The rotary latch, in particular a finger and part of a basic body of the rotary latch, is able to pivot past the stop element. 
         [0006]    EP 1 606 484 B1 discloses a locking unit for an engine hood of a motor vehicle having a rotary latch and a stop element on a side plate of a lock housing. The stop element juts outward from the lock housing. 
         [0007]    These types of locking units serve, for example, for locking a backrest of a vehicle seat to a seat part and/or to a bodywork or structure of a vehicle or for locking the vehicle seat to the bodywork or structure of the vehicle. Engine hoods, trunk lids or doors of vehicles can also be locked to the bodywork or structure of the vehicle with such locking units. 
         [0008]    The locking unit comprises a housing which includes two side plates. In the locked state, the locking bolt fits in a receiving opening of the housing and in a hook aperture of the rotary latch. The rotary latch is an extensively flatly formed component which comprises a material thickness of only a few millimeters. 
         [0009]    As a result of tolerances in the vehicle or in the vehicle seat, the locking bolt can become skewed relative to the rotary latch such that the locking bolt is no longer aligned parallel to the rotational axis of the rotary latch, but is at a slant thereto. This can result in noise problems when, for example, the rotary latch is somewhat tilted in its bearing position by the inclined locking bolt and, as a result, comes into contact with the housing. In addition, the skewed position of the rotary latch increases the tensioning distance of the locking bolt. The tensioning distance is the smallest measurement between the support surface of the locking bolt at the receiving opening of the housing, on the one hand, and the oppositely situated support surface of the locking bolt at the hook aperture of the rotary latch on the other hand. In the tolerance-free case, where the bolt cross section is circular and support surfaces are arranged distributed about 180° over the bolt circumference between, on the one hand, the locking bolt and the receiving opening of the housing and, on the other hand, the locking bolt and the hook aperture of the rotary latch, the tensioning distance is equal the bolt diameter. 
         [0010]    An increase in the tensioning distance results in a play-free position that is provided in the locking unit only having a limited effect as the rotary latch is not able to rotate far enough in the direction of its locking position. Where there is a severe increase in the tensioning distance, the latching pawl is not able to drop in or is not able to drop in completely. The rotary latch is not then secured in the locked state. In addition, the skewed position of the locking bolt results in a loss of overlap between the rotary latch and the latching pawl, which can reduce the strength of the locking unit. 
       SUMMARY OF THE INVENTION 
       [0011]    An object underlying the invention is to improve a locking unit of the type named in the introduction, in particular, when using the locking unit in a vehicle seat, to make said locking unit less sensitive to angular and/or positional tolerances between the rotary latch and the locking bolt. 
         [0012]    Said object is achieved according to the invention by a locking unit for a vehicle seat, said locking unit including a lock housing with a receiving opening for receiving a locking bolt, as well as a rotary latch which is mounted so as to be pivotable about a first bearing bolt and comprises a hook aperture for locking with a locking bolt, wherein the bearing bolt is aligned in an axial direction, and the receiving opening is defined by a stop element, the stop element provides a stop for a locking bolt which is situated in the hook aperture, and the stop element projects into the lock housing in the axial direction. In a locked state of the locking unit with the locking bolt extending precisely in the axial direction, a first contact region between the locking bolt and the stop element and a second contact region between the locking bolt and the rotary latch overlap in part in the axial direction, or the first contact region is located completely inside the second contact region in the axial direction. 
         [0013]    The first contact region is the sum of the contact surfaces between the locking bolt and the stop element, it also being possible for the contact surfaces to be punctiform or linear and, as a result, being able to comprise a very small surface area. The first contact region can consist of precisely one contact surface or from several contact surfaces. Individual contact surfaces of the first contact surface can be arranged offset with respect to one another without touching one another. The second contact region is the sum of the contact surfaces between the locking bolt and the rotary latch, it also being possible for the contact surfaces to be punctiform or linear and, as a result, being able to comprise a very small surface area. The second contact region can consist of precisely one contact surface or from several contact surfaces. Individual contact surfaces of the second contact surface can be arranged offset with respect to one another without touching one another. 
         [0014]    The first contact region overlapping the second contact region in the axial direction means that in a cylindrical coordinate system aligned in the axial direction, part regions of the first contact region and part regions of the second contact region have said same axial coordinates without in this case having to touch one another. The first contact region being located in the axial direction fully inside the second contact region means that in a cylindrical coordinate system aligned in the axial direction, the first contact region has exclusively axial coordinates which also comprise the second contact region. 
         [0015]    A generic locking unit for a vehicle seat includes a lock housing with a receiving opening for receiving a locking bolt, as well as a rotary latch which is pivotably mounted and comprises a hook aperture for locking with a locking bolt. 
         [0016]    According to the invention, the receiving opening is defined by a stop element which provides a stop for a locking bolt, which is located in the hook aperture, and which projects into the lock housing in the axial direction. 
         [0017]    As a result, the distance between the first contact region and the second contact region in the axial direction is reduced. As a result, the tensioning distance in the case of a slanting locking bolt is also reduced and consequently the locking unit is less sensitive to angular and/or positional tolerances between the rotary latch and the locking bolt. 
         [0018]    The lock housing preferably includes at least one side plate in which the receiving opening is realized. Another second side plate, which is arranged approximately parallel to the first side plate, is advantageously provided, the receiving opening being realized in both side plates together. 
         [0019]    In this case, the stop element projects advantageously into the lock housing in the axial direction from the side plate. 
         [0020]    According to an advantageous development of the invention, the stop element is formed by bending a tab which is provided on the side plate. In this way, the production of the stop element and of the locking unit is relatively simple. 
         [0021]    In an advantageous manner, the tab, in this case, is bent about a bending angle of approximately between 75° and 85°. In a particularly advantageous manner, the tab is bent about a bending angle of approximately 80°. As a result, the first contact region of the locking bolt with the stop element is severely reduced in the axial direction and is to be seen as approximately punctiform. In this way, the distance between the first contact region and the second contact region always remains minimal in the axial direction. A bending angle of 90° provides a maximum contact surface of the first contact region and consequently reduces the surface pressure. 
         [0022]    In a particularly advantageous manner, the first contact region of the locking bolt with the stop element is located, with reference to the locking bolt, diametrically opposite the second contact region of the locking bolt with the rotary latch. 
         [0023]    The hook aperture of the rotary latch is preferably defined by a nose (nose portion) and a finger (finger portion). In this case, the nose of the rotary latch serves for holding the locking bolt in the locked state of the locking unit. The finger of the rotary latch serves for ejecting the locking bolt during unlocking. In addition, the locking bolt presses onto the finger during locking and as a result pivots the rotary latch into its closed position. 
         [0024]    According to an advantageous further development of the invention, the rotary latch comprises a basic body with an approximately constant thickness, wherein the thickness of the finger is less than the thickness of the basic body. The finger can consequently pivot past the side of the stop element. 
         [0025]    The basic body can be formed, in particular punched, from a metal sheet. The reduced thickness of the finger can be generated in one production method step as a result of bending the metal sheet in the region of the finger. The finger, in this case, can be realized integrally with the basic body of the rotary latch. The finger can be arranged eccentrically in the axial direction with respect to the basic body of the rotary latch. The locking unit is constructed in a particularly compact manner by the finger closing off flush with the basic body on one side. 
         [0026]    The finger can also be realized as a separate part. In particular, the finger can be an injected plastics material part. 
         [0027]    In an advantageous manner, the stop element is arranged offset with respect to the finger in the axial direction such the finger is able to pivot past the side of the stop element. The stop element can overlap the basic body of the rotary latch in the axial direction as a result of the lesser thickness of the finger without there being collisions between the stop element and the rotary latch during a function-related rotation of the rotary latch. 
         [0028]    In an advantageous manner, the nose comprises a chamfer on at least one edge which faces the hook aperture. As a result, the second contact region of the locking bolt with the rotary latch is reduced in the axial direction. 
         [0029]    Each edge of the nose facing the hook aperture preferably comprises one chamfer each. Both chamfers preferably comprise a similar cross section. 
         [0030]    According to a further development of the invention, the two chamfers merge into one another in the axial direction. As a result, the second contact region is severely reduced in the axial direction and is to be seen as approximately punctiform. 
         [0031]    According to an advantageous development of the invention, the surface of the nose which faces the locking bolt is realized in a convexly curved manner. As a result, the second contact region is severely reduced in the axial direction and is to be seen as approximately punctiform. In addition, the surface pressure of the nose of the rotary latch onto the locking bolt is reduced. 
         [0032]    Said object is also achieved by a vehicle seat which includes at least one locking unit according to the invention. 
         [0033]    The invention is explained in more detail below by way of an advantageous exemplary embodiment shown in the figures. However, the invention is not restricted to said exemplary embodiment. 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 the embodiment of the invention is illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]    In the drawings: 
           [0035]      FIG. 1  is a schematic representation of a vehicle seat; 
           [0036]      FIG. 2  is a section through a locking unit according to the prior art; 
           [0037]      FIG. 3  is a side view of a locking unit according to the prior art; 
           [0038]      FIG. 4  is a sectional view along the line A-A from  FIG. 3 ; 
           [0039]      FIG. 5  is a side view of a locking unit according to a first exemplary embodiment; 
           [0040]      FIG. 6  is a section along the line B-B from  FIG. 5 ; 
           [0041]      FIG. 7  is a side view of a locking unit according to a second exemplary embodiment; 
           [0042]      FIG. 8  is a section along the line C-C from  FIG. 7 ; 
           [0043]      FIG. 9  is a side view of a rotary latch according to the prior art with the locking bolt at a slant; 
           [0044]      FIG. 10  is a side view of a rotary latch according to the first exemplary embodiment with the locking bolt at a slant; 
           [0045]      FIG. 11  is a side view of a rotary latch according to the second exemplary embodiment with the locking bolt at a slant; and 
           [0046]      FIG. 12  is a perspective representation of a rotary latch according to the first and the second exemplary embodiment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0047]    A locking unit  10  is provided in a motor vehicle for connecting a structural part, in the present case a backrest  3 , of a vehicle seat  1 , in particular a rear seat, to a vehicle structure. The backrest  3 , in this case, is attached to a seat part  5  so as to be pivotable from a position of use into a position of non-use. 
         [0048]    The locking unit  10  is also usable in other places, 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. 
         [0049]    The arrangement of the vehicle seat  1  inside the vehicle and the usual direction of travel of the same are defined by the direction information used below. In this case, a direction oriented perpendicular to the ground is designated below as the vertical direction and a direction perpendicular to the vertical direction and perpendicular to the direction of travel is designated below as the transverse direction. 
         [0050]    The locking unit  10  comprises a lock housing which includes a first side plate  16  and a second side plate (not shown). The surface areas of the first side plate  16  and of the second side plate are developed in an extensively flat manner in the present case and are arranged in a plane defined by the direction of travel and the vertical direction, that is to say perpendicular to the transverse direction. The first side plate  16  and the second side plate each include two bearing bores which are realized in a circular manner in the present case. 
         [0051]    An in particular slot-shaped receiving opening  19 , which opens in particular in a funnel-shaped manner in the direction of a locking bolt  12  in order to receive the same for locking, is realized in the first side plate  16  and in the second side plate. In the present case, the locking unit  10  in this case is fastened on the backrest  3  and the locking bolt  12  on the vehicle structure. It is also conceivable for the locking unit  10  to be fastened on the vehicle structure  12  and the locking bolt  12  on the backrest  3 . 
         [0052]    A rotary latch  20  is pivotably mounted on a first bearing bolt  51  which is fastened, in turn, on the first side plate  16  and on the second side plate. The first bearing bolt  51  is inserted into one bearing bore each of the first side plate  16  and of the second side plate. The first bearing bolt  51  consequently extends horizontally in the transverse direction in the present case. The preferably metal first bearing bolt  51  is riveted or caulked with the first side plate  16  and the second side plate in the present case. The bearing bolt  51  is extensively rotationally symmetrical about the center axis M. The bearing bolt is aligned in the direction of the center axis M. A direction which is defined by the center axis M of the first bearing bolt  51  is designated below as the axial direction. Consequently, the bearing bolt  51  is aligned in the axial direction. In this case, the term axial direction includes all vectors which extend parallel to the center axis M, irrespective of whether or not they are in alignment with the center axis M. 
         [0053]    The portion of the locking bolt  12  to be received by the receiving opening  19  extends in the axial direction in the case of optimum mounting. In practice, in the majority of cases the locking bolt  12  extends in a slightly slanting manner with respect to the axial direction on account of tolerances. 
         [0054]    The rotary latch  20  comprises a rotary latch hole  24  which, in the present case, is realized as a circular opening and which is penetrated by the first bearing bolt  51 . The rotary latch  20  is prestressed in the opening direction by means of a spring. The bearing bolt  51  mounts the rotary latch  20  so that it is pivotable. 
         [0055]    The rotary latch  20  additionally comprises a hook aperture  21  for interaction with the locking bolt  12 . On the side located away from the rotary latch hole  24 , the hook aperture  21  is defined at the side by a nose  28  of the rotary latch  20 . On the side facing the rotary latch hole  24 , the hook aperture  21  is defined at the side by a finger  26  of the rotary latch  20 . In the present case, the finger  26  is realized integrally with the basic body of the rotary latch  20 . However, the finger  26  can also be realized as a separate part, in particular as a plastics part injected onto the rotary latch  20 . 
         [0056]    The rotary latch  20  comprises a function surface  22  for interaction with a latching pawl  30  and a tensioning element  40 . In the locked state, the function surface  22  points approximately in the direction of a second bearing bolt  52 , which is arranged parallel to the first bearing bolt  51  and pivotably mounts the latching pawl  30  and the tensioning element  40 . The function surface  22 , in the present case, is realized in a planar manner, but can also be curved arcuately, for example, and realized in a convex or concave manner. 
         [0057]    The second bearing bolt  52  is also inserted into one bearing bore each of the first side plate  16  and of the second side plate. The second bearing bolt  52  consequently also extends in the axial direction which, in the present case, corresponds to the transverse direction. The preferably metal second bearing bolt  52  is riveted or caulked with the first side plate  16  and the second side plate in the present case. 
         [0058]    The rotary latch  20  is realized in the same manner in the case of the first and the second exemplary embodiment and comprises a basic body which is defined for the most part in each case in the axial direction by a flat surface area. The width of the function surface  22  corresponds to the thickness of the basic body of the rotary latch  20 , that is to say the extension of the basic body in the axial direction. 
         [0059]    The thickness of the nose  28  also corresponds extensively to the thickness of the basic body of the rotary latch  20 . The nose  28 , however, comprises a chamfer  29  on each of the two sides on the edges facing the hook aperture  21 . 
         [0060]    The thickness of the finger  26 , however, is less than the thickness of the basic body of the rotary latch  20 . In the present case, the thickness of the finger  26  is approximately a third of the thickness of the basic body of the rotary latch  20 . 
         [0061]    The tensioning element  40  is mounted so as to be pivotable on the second bearing bolt  52 . To this end, the tensioning element  40  comprises a tensioning element hole which, in the present case, is circular and is penetrated by the second bearing bolt  52 . The tensioning element  40  is prestressed toward the rotary latch  20  by means of a spring. 
         [0062]    In the locked state, when the hook aperture  21  of the rotary latch  20  receives the locking bolt  12  and extends transversely with respect to the receiving opening, the tensioning element  40 , as the securing element, exerts a closing torque onto the rotary latch  20 . To this end, the tensioning element  40  comprises a tensioning surface  41  which is curved eccentrically with respect to the second bearing bolt  52  and is situated in non-self-locking contact with the function surface  22  of the rotary latch  20 . The tensioning surface  41  is arcuately curved in the present case and is realized in a convex manner. 
         [0063]    The latching pawl  30  is arranged adjacent the tensioning element  40  on the second bearing bolt  52  and is also mounted so as to be pivotable on the second bearing bolt  52 , that is to say in alignment with the tensioning element  40 . To this end, the latching pawl  52  comprises a latching pawl hole which is circular in the present case and is penetrated by the second bearing bolt  52 . The latching pawl  30  is prestressed toward the rotary latch  20  by means of a spring. 
         [0064]    The tensioning element  40  is arranged adjacent the first side plate  16  in the present case and the latching pawl  30  is arranged adjacent the second side plate in the present case. The latching pawl  30  and the tensioning element  40  are coupled with play for entrainment, for example by means of a slot/pivot guide or by means of an axially protruding entrainment means. 
         [0065]    The latching pawl  30  comprises a latching surface  31  which is situated in the vicinity of the tensioning surface  41  of the tensioning element  40 . In the locked state, the latching surface  31  is positioned at a spacing to the function surface  22  of the rotary latch  20 . In the present case, the latching surface  31  is curved arcuately and is realized in a convex manner, but can also be planar. 
         [0066]    The width of the function surface  22 , which corresponds to the thickness of the basic body of the rotary latch  20 , also corresponds approximately to the sum of the thickness of the latching pawl  30  and of the thickness of the tensioning element  30 . The rotary latch  20  therefore comprises approximately the same material thickness as the material thicknesses of the latching pawl  30  and of the tensioning element  40  together. 
         [0067]    If, in the event of a crash, the rotary latch  20  experiences an opening torque and the tensioning element  40  is pressed away somewhat, the latching surface  31  moves into abutment against the function surface  22  of the rotary latch  20 . Thus, the latching pawl  39  serves for supporting the rotary latch  20  and, as a further securing element, prevents the rotary latch  20  rotating further in the opening direction. Consequently, the latching pawl  30  prevents the rotary latch  20  from opening. 
         [0068]    In the locked state of the locking unit  12 , the locking bolt  12  is situated in the receiving opening  19 , which is realized in the first side plate  6  and in the second side plate, and in the hook aperture  21  of the closed rotary latch  20 . The receiving opening  19  and the hook aperture  21  extend crosswise with respect to one another in the locked state. The tensioning element  40  secures the rotary latch  20  as a result of interaction between the tensioning surface  41  and the function surface  22 . The latching surface  31  of the latching pawl  30  is at a slight spacing from the function surface  22  of the rotary latch  20 . 
         [0069]    For opening the locking unit  10 , the latching pawl  30  is pivoted away from the rotary latch  20  by means of an unlocking lever  35 , as a result of which the latching surface  31  of the latching pawl  30  is removed further from the function surface  22  of the rotary latch  20 . The latching pawl  30  entrains the tensioning element  40  on account of the entrainment coupling such that the rotary latch  20  is no longer secured. The latching pawl  30 , in this case, also entrains the rotary latch  20 , as a result of which said rotary latch opens, that is to say pivots in the opening direction. 
         [0070]    On account of the pivoting movement of the rotary latch  20 , the hook aperture  21  is pulled back from the receiving opening  19  realized in the first side plate  16  and in the second side plate and releases the locking bolt  12  which is removed in opposition to the pivoting-in direction of the locking unit  10 . If the locking bolt  12  has left the hook aperture  21 , the locking unit  10  is situated in the unlocked state. 
         [0071]    If in said unlocked state the locking bolt  12  moves back into the receiving opening  19  which is formed in the first side plate  16  and in the second side plate and into abutment against the finger  26 , the locking bolt  12  presses the rotary latch  20  into its closed position. The tensioning element  40  is moved along the function surface  22 . Entrained by the tensioning element  40  or on account of the prestressing of a spring, the latching pawl  30  pivots toward the rotary latch  20 , the latching surface  31  approaching the function surface  22  of the rotary latch  20  and being located opposite the same at a small spacing. The locking unit  10  is then in the locked state again. 
         [0072]    In the case of a locking unit  10  disclosed in the prior art and shown in  FIGS. 3 and 4 , the receiving opening  19  is defined by a stop region  60  which is provided in each case on the first side plate  16  and on the second side plate. 
         [0073]    In the locked state, the locking bolt  12 , insofar as it extends precisely parallel to the bearing bolts  51 ,  52  in the axial direction, abuts against the stop regions  60  on the first side plate  16  and the second side plate. The stop regions  60  on the first side plate  16  and the stop region on the second side plate together form a first contact region  71 . The first contact region  71  is the sum of the contact surfaces between the locking bolt  12  and the stop regions  60 . On the side located opposite the stop regions  60 , the locking bolt  12  is in contact with the nose  28  of the rotary latch  20  in a second contact region  72 . The second contact region  72  is the sum of the contact surfaces between the locking bolt and the rotary latch. The stop region  60  on the first side plate  16 , the second contact region  72  of the locking bolt  12  with the nose  28  of the rotary latch  20  and the stop region on the second side plate are therefore located offset to one another in the axial direction. Consequently, the first contact region  71  and the second contact region  72  are arranged in such a manner that they do not overlap in the axial direction. The first contact region  71  consists of two contact surfaces which are spaced apart from one another and receive the second contact region  72  between them. 
         [0074]    If the locking bolt  12  does not extend precisely parallel to the bearing bolts  51 ,  52  in the axial direction, but rather at a slant with respect to the axial direction, the locking bolt  12  abuts either against the stop region  60  of the first side plate  16  or against the stop region of the second side plate. In addition, the locking bolt  12  abuts against an edge of the nose  28  of the rotary latch  20 . 
         [0075]    From a certain slant of the locking bolt  12  with respect to the axial direction, the locking bolt  12 , when the locking unit  10  is closed, prevents the rotary latch  20  from dropping in fully. In addition, the tensioning element  40  is blocked by the rotary latch  20  and the tensioning surface  41  cannot move into contact with the function surface  22 . Consequently, the tensioning element  40  cannot exert any closing torque onto the rotary latch  20  for tolerance compensation. Such a position of the rotary latch  20  and of the tensioning element  40  is shown in  FIG. 9 . 
         [0076]    According to a first exemplary embodiment shown in  FIGS. 5 and 6 , the first side plate  16  comprises a stop element  61  which defines the receiving opening  19 . The stop element  61 , in the present case, is formed by bending a tab which is provided on the first side plate  16 . The tab, in this case, is bent by approximately 90°, the stop element  61  consequently extends into the lock housing of the locking unit  10  in the axial direction at right angles to the rest of the first side plate  16 . 
         [0077]    The stop element  61  is therefore realized integrally with the first side plate  16  in the present case. The stop element  61  extends in the axial direction up to just in front of the finger  26  of the rotary lock  20  without touching said finger. 
         [0078]    In the locked state, the locking bolt  12 , insofar as it extends precisely parallel to the bearing bolts  51 ,  52  in the axial direction, abuts flatly against the stop element  61 . On the side located opposite the stop element  61 , the locking bolt  12  is in contact with the nose  28  of the rotary latch  20 , with the region which is located between the chamfers  29 . 
         [0079]    The first contact region  71  of the locking bolt  12  with the stop element  61  consequently extends approximately over the entire length of the stop element  61  in the axial direction. The second contact region  72  of the locking bolt  12  with the rotary latch  20  extends in the axial direction approximately over the region of the nose  28  which is located between the chamfers  29 . The first contact region  71  of the locking bolt  12  with the stop element  61  and the oppositely situated second contact region  72  of the locking bolt  12  with the rotary latch  20  overlap in part in the axial direction. 
         [0080]    If the locking bolt  12  does not extend precisely parallel to the bearing bolts  51 ,  52  in the axial direction, but in a slanting manner with respect to the axial direction, the second contact region  72  of the locking bolt  12  with the rotary latch  20  is displaced in the axial direction to an edge of one of the two chamfers  29  on the nose  28 . The first contact region  71  of the locking bolt  12  with the stop element  61  is also displaced. Depending on the orientation of the slant of the locking bolt  12 , the first contact region  71  of the locking bolt  12  with the stop element  61  is located at the end of the stop element  61 , that is to say centrally in the lock housing of the locking unit  10 , or in the vicinity of the transition between the side plate  16  and the stop element  61 . 
         [0081]    In the first case, when the first contact region  71  of the locking bolt  12  with the stop element  61  is located centrally in the lock housing of the locking unit  10 , the second contact region  72  of the locking bolt  12  with the rotary latch  20  is located only slightly away from the first contact region  71  of the locking bolt  12  with the stop element  61  in the axial direction. In said case, the slant of the locking bolt  12  only has a relatively small effect on the position of the rotary latch  20  during locking. 
         [0082]    In the second case, when the first contact region  71  of the locking bolt  12  with the stop element  61  is located in the vicinity of the transition between the side plate  16  and the stop element  61 , the second contact region  72  of the locking bolt  12  with the rotary latch  20  is located further away from the first contact region  71  of the locking bolt  12  with the stop element  61  than in the above-described first case, but not so far as in the case of a locking unit  10  according to the prior art. 
         [0083]    Up to a certain slant of the locking bolt  12  with respect to the axial direction, the tensioning surface  41  of the tensioning element  40  still comes into the contact with the function surface  22  of the rotary latch  20  and the tensioning element  40  exerts a closing torque onto the rotary latch  20  for tolerance compensation. Such a position of the rotary latch  20  and of the tensioning element  40 , where the tensioning surface  41  is just in contact with the function surface  22 , is shown in  FIG. 10 . 
         [0084]    According to a second exemplary embodiment shown in  FIGS. 7 and 8 , the first side plate  16  also comprises a stop element  61  which defines the receiving opening  19 . The stop element  61 , in the present case, is formed by bending a tab which is provided on the first side plate  16 . In this case, in contrast to the first exemplary embodiment, the tab is bent by a bending angle W of approximately 80°. The stop element  61  consequently extends into the lock housing of the locking unit  10  in a slanting manner with respect to the rest of the first side plate  16  and in a slanting manner with respect to the axial direction. 
         [0085]    The stop element  61 , in the present case, is realized integrally with the first side plate  16 . The stop element  61  extends in the axial direction up to just in front of the finger  26  of the rotary latch  20  without touching said finger. 
         [0086]    In the locked state, the locking bolt  12 , insofar as it extends precisely parallel to the bearing bolts  51 ,  52  in the axial direction, abuts against the end of the stop element  61 , that is to say centrally in the lock housing of the locking unit  10 . The first contact region  71  between the stop element  61  and the locking bolt  12  is approximately punctiform. On the side located opposite the stop element  61 , the locking bolt  12  is in contact with the nose  28  of the rotary latch  20 , with the region which is located between the chamfers  29 . 
         [0087]    The second contact region  72  of the locking bolt  12  with the rotary latch  20  extends in the axial direction approximately over the region of the nose  28  which is located between the chamfers  29 . The first contact region  71  of the locking bolt  12  with the stop element  61  is consequently located in the axial direction inside the second contact region  72  of the locking bolt  12  with the rotary latch  20 , preferably centrally. The first contact region  71  of the locking bolt  12  with the stop element  61  is located, with reference to the locking bolt  12 , diametrically opposite the second contact region  72  of the locking bolt  12  with the rotary latch  20 . 
         [0088]    It is also conceivable for the two chamfers  29  to merge into one another in the axial direction. As a result, the second contact region  72  is approximately punctiform in the axial direction. The nose  28  of the rotary latch  20  therefore comprises an edge on its side that faces the locking bolt  12 . It is also conceivable for the surface of the nose  28  that faces the locking bolt  12  to be realized in a convexly curved manner. The second contact region  72  is also approximately punctiform as a result. The punctiform first contact region  71  is then located, with reference to the locking bolt  12 , diametrically opposite the punctiform second contact region  72 . 
         [0089]    If the locking bolt  12  does not extend precisely parallel to the bearing bolts  51 ,  52  in the axial direction, but rather at a slant with respect to the axial direction, the second contact region  72  of the locking bolt  12  with the rotary latch  20  is displaced in the axial direction to an edge of one of the two chamfers  29  on the nose  28 . However, the first contact region  71  of the locking bolt  12  with the stop element  61  is not displaced, but remains at the end of the stope element  61 , that is to say centrally in the lock housing of the locking unit  10 . 
         [0090]    The second contact region  72  of the locking bolt  12  with the rotary latch  20  is consequently located only slightly away from the first contact region  71  of the locking bolt  12  with the stop element  61  in the axial direction. Consequently, the slanting of the locking bolt  12  only has a relatively small effect on the position of the rotary latch  20  during locking. 
         [0091]    During locking, the tensioning surface  41  of the tensioning element  40  moves into contact with the function surface  22  of the rotary latch  20  and the tensioning element  40  exerts a closing torque onto the rotary latch  20  for tolerance compensation. Such a position of the rotary latch  20  and of the tensioning element  40  is shown in  FIG. 11 . 
         [0092]    In the case of the first exemplary embodiment shown in  FIG. 5  and  FIG. 6 , as well as in the case of the second exemplary embodiment shown in  FIG. 7  and  FIG. 8 , the stop element  61  is arranged in each case offset in the axial direction with respect to the finger  26  of the rotary latch  20 . As a result, during the locking and during the unlocking of the locking unit  10 , the finger  26  pivots past the stop element  61 , preferably without touching said stop element. 
         [0093]    The features disclosed in the preceding description, the claims and the drawings can be significant to the realization of the invention in their different developments both on their own and in combination. 
         [0094]    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.