Abstract:
A vehicle seat fitting has a fitting parts ( 11, 12 ) have a sprocket ( 17 ) and guide segments ( 14 ), a bar ( 16 ) guided by the guide segments between a locked and unlocked state that interact with the sprocket. The bar has bar cams ( 16   a,    16   b ). An eccentric ( 27 ) is rotatably mounted around a rotation axis (A) and in a transition from unlocked to the locked, engages the bar with a force for clamping the bar against the sprocket. The eccentric has eccentric cams ( 28, 128 )interacting with the bar cams. The first eccentric cam has a cam section ( 28.2 ) which runs in the peripheral direction concentrically around the axis. The cam section is arranged upstream in the closing direction of a further cam section ( 28.4 ) that has a cam contour running radially outwards downstream in the closing direction relative to the concentrically peripheral contour for clamping the bar against the sprocket.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a United States National Phase Application of International Application PCT/EP2013/070151 filed Sep. 27, 2013 and claims the benefit of priority under 35 U.S.C. §119 of German Patent Applications DE 10 2012 019 698.9 filed Oct. 4, 2012 and DE 10 2012 023 057.5 filed Nov. 22, 2012, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a fitting for a vehicle seat, in particular for a motor vehicle seat, having a first fitting part and a second fitting part which are able to be rotated relative to one another about an axis, wherein a toothed ring is formed on the first fitting part and guide segments are formed on the second fitting part, at least one locking bar which is radially displaceably guided by means of the guide segments between a locked state and an unlocked state, and which in the locked state cooperates with the toothed ring in order to lock the fitting, wherein the at least one locking bar has a first locking cam and a second locking cam, and a rotatably mounted eccentric which during the transition from the unlocked state into the locked state by being rotated in a closing direction subjects the locking bar to a force for clamping the locking bar against the toothed ring. 
       BACKGROUND OF THE INVENTION 
       [0003]    Generic fittings have at least one locking bar and one rotatable eccentric. The eccentric holds the at least one locking bar, in a manner in which it is spring-loaded, in engagement with a toothing of a toothed ring. The eccentric contour is designed to be self-locking, i.e. a transmission of force from the toothed segment to the eccentric under static load conditions or impulse loads does not lead to a rotation of the eccentric and as a result does not lead to an opening of the fitting. Unfavorable load conditions, however, in particular cyclical or vibratory stresses, may lead under adverse conditions to an undesired rotation of the eccentric and as a result to an undesired opening of the fitting. 
         [0004]    When mounting a generic fitting, an eccentric angle which defines the angular position of the eccentric relative to a component of the fitting which is fixed in terms of rotation is used to monitor a fully locked position. Known eccentrics have the drawback that it is difficult to detect whether the measured eccentric angle is still within an admissible eccentric angular range defined by permitted component tolerances. Inaccuracies in terms of measurements and/or readings of the eccentric angle may lead to a false assessment of the fitting. 
         [0005]    A generic fitting is disclosed in DE 10 2010 053 525 B3 in which, in a first contact point between a first eccentric cam and a first locking cam, a first wedge angle is defined, said first wedge angle being positive, and in a second contact point which is produced only under load between the second eccentric cam and the second locking cam, a second wedge angle is defined, said second wedge angle being negative. The positive wedge angle on the first cam pair serves for locking the locking bar and for compensating for tolerances. A normal force with an opening component transmitted from the locking bar via the first cam pair to the eccentric is compensated by frictional forces in a self-locking manner. The negative wedge angle on the second cam pair serves for blocking the rotation of the eccentric under load, as the normal force in this case has a closing component. In practice, it has been shown that this system consisting of a first and second wedge angle is very sensitive to tolerances. 
         [0006]    A fitting with a locking bar is disclosed in DE 44 19 411 A1, said locking bar in each case having a bearing surface in two partial regions of the locking bar offset axially and radially to one another. An eccentric is provided for locking the locking bar and thus the fitting, said eccentric being floatingly coupled to a drive bushing. The eccentric comprises a cam with a clamping surface which continuously rises from one end to the other end of the cam and cooperates in a locking manner with one of the two bearing surfaces. The drive bushing comprises a further cam with a concentric interception surface which cooperates with the other of the two bearing surfaces. The two cams in the peripheral direction are only slightly offset relative to one another and during the locking of the fitting are rotated at the same time below the assigned bearing surfaces. As a result, with a small angle of rotation of the eccentric, the cam already bears with the clamping surface against the locking bar. This small angle of rotation makes it complicated to assess the locked state of the fitting in a reliable manner by using the eccentric angle. 
         [0007]    EP 1 591 303 A2 discloses a further fitting with an eccentric which has two eccentric cams for supporting a locking bar. It is not disclosed how the eccentric cams have to be designed so that the locked state of the fitting may be assessed reliably using the eccentric angle. 
       SUMMARY OF THE INVENTION 
       [0008]    An object of the invention is to improve a fitting of the type mentioned in the introduction, in particular to design said fitting so that it is less sensitive to tolerances. Secure locking is intended to be ensured even under unfavorable load conditions, and a simpler option is provided to assess the locked state of the fitting reliably using the eccentric angle. An object of the invention is to improve a vehicle seat by using a fitting with optimized locking security. 
         [0009]    According to the invention, a fitting for a vehicle seat, in particular for a motor vehicle seat is provided comprising a first fitting part and a second fitting part which are able to be rotated relative to one another about an axis. A toothed ring is formed on the first fitting part and guide segments are formed on the second fitting part. At least one locking bar is radially displaceably guided, by means of the guide segments, between a locked state and an unlocked state. In the locked state the at least one locking bar cooperates with the toothed ring in order to lock the fitting. The at least one locking bar has a first locking cam and a second locking cam. A rotatably mounted eccentric, which during the transition from the unlocked state into the locked state by being rotated in a closing direction, subjects the locking bar to a force for clamping the locking bar against the toothed ring. For acting on the locking bar the eccentric has a first eccentric cam which is suitable for cooperating with the first locking cam and a second eccentric cam which is suitable for cooperating with the second locking cam. The first eccentric cam has a cam portion which extends in the peripheral direction concentrically about the axis. The cam portion extending concentrically about the axis is arranged counter to the closing direction in front of a further cam portion of the first eccentric cam. The further cam portion counter to the closing direction has a cam contour which extends radially outwardly relative to a concentric peripheral contour, for clamping the locking bar against the toothed ring. 
         [0010]    As the first eccentric cam has a cam portion which extends in the peripheral direction concentrically about the axis and as said cam portion extending concentrically about the axis is arranged counter to the closing direction in front of a further cam portion of the first eccentric cam, and the further cam portion counter to the closing direction has a cam contour extending radially outwardly relative to a concentric peripheral contour, for clamping the locking bar in the toothed ring, it is achieved that the eccentric of a fitting with inadmissibly high tolerances in the locked state, in comparison with a fitting with components of nominal size, has a rotational angular deviation in the direction of an open fitting which is able to be measured in a clear and reliable manner. 
         [0011]    The directional information used “counter to the closing direction” is of equivalent meaning to a viewing direction counter to the closing direction. When rotating the eccentric in the closing direction, the front cam portions counter to the closing direction accordingly reach the assigned locking cams first. 
         [0012]    In the unlocked state, irrespective of the exemplary embodiment, the eccentric of the fitting is rotated sufficiently far counter to the closing direction and the locking bar is moved sufficiently far radially inwardly that the first locking cam of the locking bar pulled radially inwardly is located in an intermediate space between side contours of the first and second eccentric cams extending in the radial direction. If, during locking and due to a first locking cam located too far radially on the inside, the eccentric is no longer able to reach its designated locked position, as the first eccentric cam with the concentric cam portion in the radial direction does not fit below the first locking cam, the eccentric remains open at least by an eccentric angle measurement which is able to be measured in a reliable manner and which corresponds to the length of the concentric cam portion. This angular step is able to be identified more easily than if the eccentric rotational angle were to be continuously altered and only a limit for the permitted angular value were to be set. This simplifies the assessment of the mounted fittings relative to the reliable function thereof. 
         [0013]    In comparison with the prior art, as the first eccentric cam has a cam portion which in the peripheral direction extends concentrically about the axis A, a negative wedge angle on a second cam pair may be dispensed with. As a result, the system is less sensitive to tolerances. 
         [0014]    The introduction of a precisely concentric cam portion (zero degree contour) on the first eccentric cam is the preferred solution. The term concentric also encompasses here quasi-concentric cam portions which have a very small angle between a tangent on the quasi-concentric cam portion and a circular arc extending about the axis of the eccentric, which ideally is approximately half as big or smaller than the angle in a fourth cam portion of the locking contour of the first eccentric cam. By means of the reduced angle, smaller force components are produced in the opening rotational direction of the eccentric and greater frictional force components which hold the eccentric in the locked position are produced. 
         [0015]    If under adverse conditions the eccentric were to be subjected to opening forces, a potentially undesired eccentric movement will stop after an eccentric rotational angle of preferably ca. 4°(alternatively up to ca. 8°) with the contact of the first locking cam on the concentric contact point of the first eccentric cam. Thus, a sufficient locking of the fitting is ensured. 
         [0016]    The concentric contact surface leads to a slight increase in operating force during the unlocking of the fitting and thus provides an easily perceivable indicator as to when the unlocking point is reached and the fitting released. After leaving the concentric contact surface an actuation is carried out again with lower operating force. This advantageously leads to a clearer measurement result by means of the specific force path/rotational angle path during a functional test of the fitting. 
         [0017]    Preferably, the first eccentric cam has a first cam portion which defines a control contour by means of a rounded portion of a first flank of the eccentric cam extending substantially in the radial direction, with a contour of the eccentric cam extending substantially in the peripheral direction, said control contour controlling the introduction of the locking bar into the toothed ring, whilst the eccentric rotates in the closing direction. Advantageously, a second cam portion, which is directly adjacent to the first cam portion and which extends in the peripheral direction concentrically about the axis A, forms the concentric cam portion. 
         [0018]    For providing a free pivoting function, the locked state of the fitting may be coupled to a locked state of a further fitting, so that when the fitting is open, the further fitting is also held open thereby via a coupling means, in particular a Bowden cable. An additional cam portion between the first cam portion and the second cam portion of the first eccentric cam of the fitting in this case compensates for clearance and tolerances potentially present in the coupling means. 
         [0019]    The fourth cam portion is characterized by a cam contour extending slightly radially outwardly relative to the peripheral direction—counter to the closing direction—which extends in a wedge angle which is preferably 4° to 6°. The wedge angle requires that the regions of the fourth cam portion trailing in the closing direction protrude further radially outwards than the leading regions so that the locking bar acted upon by the first eccentric cam may be locked and compensation of tolerances is possible. The region of the fourth cam portion, which leads in the closing direction, reaches the assigned first eccentric cam first during the locking procedure so that subsequently the cam contour extending radially outwardly presses the locking bar outwardly. 
         [0020]    The contour of the first locking cam is reliably prevented from becoming caught on the contour of the first eccentric cam during the rotation of the eccentric by the fitting between the second cam portion and the fourth cam portion having a third cam portion which connects together the second cam portion and the fourth cam portion continuously, in particular continuously without edges. 
         [0021]    The strength of the fitting according to the invention may be increased in the locked unloaded state of the fitting by the first eccentric cam being in contact with the first locking cam in a first contact point and a gap of, in particular, 0.05 to 0.5 mm existing between the second eccentric cam and the second locking cam. In the locked loaded state of the fitting, in particular when the vehicle seat is subjected to high forces due to a crash, the locking bar is tilted between the guide segments so that, as a result, in addition to the contact between the first eccentric cam and the first locking cam in the first contact point, the locking bar is tilted and in a second contact point the second eccentric cam is in contact with the second locking cam. 
         [0022]    The concentric cam portion of the first eccentric cam is advantageously combined with a tilting of a total of four locking bars in opposing directions. For two respective radially opposing locking bars, the first eccentric cams are arranged on the eccentric in the closing direction as the leading eccentric cams relative to the second eccentric cams; for the two other locking bars the first eccentric cams are arranged on the eccentric in the closing direction as the trailing eccentric cams relative to the second eccentric cams. Under load, when the fitting is locked, each locking bar tilts in the direction opposing the respectively adjacent locking bars. 
         [0023]    Thus, a tilting of two locking bars is ensured for both loading directions which increases the strength. 
         [0024]    The concentric cam portion is advantageously only formed on the first eccentric cams; the second eccentric cams have no contact with the second locking cams in the resting state and are formed without a concentric cam portion. In principle, however, it is also possible for all locking cams of one eccentric to be provided with a concentric cam portion. 
         [0025]    In a fitting which has at least two locking bars and just one eccentric with at least two first eccentric cams, it is sufficient if only one first eccentric cam of the at least two first eccentric cams has a cam portion extending concentrically about the axis and the remaining first eccentric cams, which have a cam portion extending concentrically about the axis, are configured so as to be correspondingly shorter in the peripheral direction. 
         [0026]    The strength of a vehicle seat with a seat part and a backrest which are connected together by means of at least one fitting may be optimized by using a fitting according to the invention. Due to the locked state of the fitting which is able to be tested in a reliable manner, the safety of the vehicle seat is further increased. 
         [0027]    The invention is described in more detail with reference to two advantageous exemplary embodiments shown in the drawings. The invention is, however, not limited to these exemplary embodiments. 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 
         [0028]    In the drawings: 
           [0029]      FIG. 1  is a schematic view of a vehicle seat with a fitting according to a first exemplary embodiment; 
           [0030]      FIG. 2  is an axial sectional view through the first exemplary embodiment; 
           [0031]      FIG. 3  is a radial sectional view through the first exemplary embodiment along the line III-III in  FIG. 2 ; 
           [0032]      FIG. 4  is a perspective view of the eccentric of the first exemplary embodiment; 
           [0033]      FIG. 5  is a front view of the eccentric of the first exemplary embodiment; 
           [0034]      FIG. 6  is a view of a detail VI of  FIG. 5 ; 
           [0035]      FIG. 7  is a view corresponding to  FIG. 3  of a locked fitting with components of nominal size; 
           [0036]      FIG. 8  is a view corresponding to  FIG. 7  of a locked fitting with components subjected to the maximum admissible tolerances; 
           [0037]      FIG. 9  is a view corresponding to  FIG. 7  of a locked fitting with inadmissibly high component tolerances; 
           [0038]      FIG. 10  is a schematic view of a vehicle seat with a fitting according to a second exemplary embodiment; 
           [0039]      FIG. 11  is a view corresponding to  FIG. 6  of the second exemplary embodiment; and 
           [0040]      FIG. 12  is a radial sectional view corresponding to  FIG. 3  through the second exemplary embodiment in the fully unlocked state. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0041]    A vehicle seat  1  for a motor vehicle has a seat part  3  and a backrest  4  which is able to be adjusted in its inclination relative to the seat part  3 . For adjusting the inclination of the backrest  4 , a transmission rod  7  is rotated manually, for example by means of a first hand lever  5 , said transmission rod being arranged horizontally in the transition region between the seat part  3  and the backrest  4 . On both sides of the vehicle seat  1  the transmission rod  7  engages in a fitting  10 . The transmission rod  7  defines the directional information of a cylinder coordinate system used. 
         [0042]    The fitting  10  has a first fitting part  11  and a second fitting part  12  which are able to be rotated relative to one another about an axis A. The axis A in the present case is aligned with the central axis of the transmission rod  7 . The two fitting parts  11  and  12  may in each case approximately describe a circular disk shape. Both fitting parts  11  and  12  preferably consist of metal, in particular steel, which may be at least partially hardened. For receiving the axially acting forces, i.e. for axially holding together the fitting parts  11  and  12 , a clasping ring  13  is provided. The clasping ring  13  preferably consists of metal, in particular steel, which is preferably unhardened. The clasping ring  13  preferably has a substantially planar annular shape but in an alternative embodiment may be profiled in an L-shape with a cylinder portion and a planar annular portion on the front face. 
         [0043]    The clasping ring  13  is connected fixedly to one of the two fitting parts  11  and  12 , in the present case in an outer annular portion to the second fitting part  12 , for example by means of laser welding or by means of a further fastening technique known per se. By means of an internal annular portion which is arranged in a plane perpendicular to the axial direction, the clasping ring  13 , optionally by the interposition of a sliding ring, encompasses the first fitting part  11  in the radial outer edge region thereof, without hindering the relative movement of the two fitting parts  11  and  12 . Additionally, the inner surfaces of the two fitting parts  11  and  12  facing one another are protected from the penetration of foreign bodies and soiling and damage. 
         [0044]    The clasping ring  13 , and the fitting part  11  or  12  fixedly connected thereto, thus clamp the other of the two fitting parts  11  and  12  which is movable relative thereto. In terms of construction, therefore, the two fitting parts  11  and  12  together form a disk-shaped unit (with the clasping ring  13 ). 
         [0045]    When mounting the fitting  10 , the first fitting part  11 , for example, is fixedly connected to the structure of the backrest  4 , i.e. fixed to the backrest. The second fitting part  12  is then fixedly connected to the structure of the seat part  3 , i.e. fixed to the seat part. The assignments of the fitting parts  11  and  12  may however also be exchanged, i.e. the first fitting part  11  could then be fixed to the seat part and the second fitting part  12  fixed to the backrest. The fitting  10  is located in the flux of force between the backrest  4  and the seat part  3 . 
         [0046]    The fitting  10  is configured as a latching fitting in which the first fitting part  11  and the second fitting part  12  are able to be locked together as disclosed, for example, in DE 10 2006 015 560 B3, the relevant disclosure thereof being expressly included therein. 
         [0047]    The second fitting part  12  has—in the present case four—guide segments  14 , which with straight guide surfaces in each case guide in pairs a locking bar  16  laterally in the radial direction. The locking bars  16 —in the present case four—are arranged offset to one another—in the present case respectively by 90°—in a constructional space defined between the two fitting parts  11  and  12 . The locking bars  16  are provided on their radially external end with a toothing which may come into (fall into) engagement with a toothed ring  17  of the first fitting part  11  configured as an internal gear. If the toothed ring  17  and the locking bars  16  cooperate, the fitting  10  is locked. In an alternative embodiment, the number of locking bars is one, two, three or more than four locking bars. 
         [0048]    The first fitting part  11  is arranged in a recess of the second fitting part  12  and is radially externally encompassed thereby, whereby the two fitting parts  11  and  12  bear one another. In this case, the radial external edge region of the first fitting part  11  with the toothed ring  17  is arranged in the radial direction between the guide segments  14  and the radial external edge region of the second fitting part  12  (serving for bearing the first fitting part  11 ). In the case of high loads, for example in the event of a crash, the first fitting part  11 —after deformation—may come to bear with its toothed ring  17  against the guide segments  14  located closer in the loading direction, which have correspondingly (concentrically) curved surfaces in the direction of the toothed ring  17 . This increases the strength of the fitting  10 . 
         [0049]    The first fitting part  11  may be mounted in the second fitting part  12 . The relationships could, however, also be reversed, i.e. the second fitting part  12  may be mounted on the first fitting part  11 . In principle, both arrangements are equivalent. 
         [0050]    A drive element  21 , for example made of plastics material, is arranged in the center of the fitting  10 , said drive element being rotatably mounted on at least one of the two fitting parts  11  and  12 , in the present case the first fitting part  11 , more specifically in a central opening thereof. On both vehicle seat sides the drive element  21  is connected fixedly in terms of rotation or at least coupled for entrainment to the transmission rod  7  which is inserted in a bore  23  of the hollow drive element  21  and on which the first hand lever  5  is located fixedly in terms of rotation. At one end of the drive element  21 , in the present case that on the second fitting part  12 , a fastening ring  24  is provided, in the present case said fastening ring consisting of plastics material and preferably being fastened by means of ultrasound welding to the drive element  21 . The first hand lever  5  may be clipped securely and fixedly in terms of rotation on the fastening ring  24 . The fastening ring  24  may also be provided at the other end of the drive element  21  or in each case at both ends. 
         [0051]    An eccentric  27  which is arranged in the constructional space defined between the fitting parts  11  and  12  is located fixedly in terms of rotation or at least coupled for entrainment on the drive element  21 . The eccentric  27  has along its external periphery for each locking bar  16 , i.e. in the present case multiplied by four, a first eccentric cam  28  which is provided for cooperating with a first locking cam  16   a  and—offset thereto in the peripheral direction—has a second eccentric cam  29  which is provided for cooperating with a second locking cam  16   b . The eccentric cams  28  and  29  face radially outward, the locking cams  16   a  and  16   b  face radially inward from the respective locking bar  16 . The eccentric cams  28  and  29  and the locking cams  16   a  and  16   b  are material portions of convex configuration, at least continuous in the region in which in each case a contact point K 1 , K 2  between the eccentric cams  28  and  29  and the respectively assigned locking cams  16   a  and  16   b  is able to bear against the respective other contact point. 
         [0052]    A spring  35 , for example a spiral spring, as is disclosed in DE 10 2009 041 492 A1, the relevant disclosure thereof being expressly included herein, is arranged in a central receiver of one of the two fitting parts  11  and  12 , in the present case of the second fitting part  12  and supported in the radial external region of the spring  35  on the second fitting part  12 . The spring  35  acts on the eccentric  27 , in the present case by being located fixedly in terms of rotation on the drive element  21  on the inside. The eccentric  27  acted upon by the spring  35  acts on the radially movable locking bars  16  and impinges on said locking bars so that they are pushed radially outwards, in order to fall into the toothed ring  17 , whereby the fitting  10  is locked. 
         [0053]    A control disk  36  is arranged axially in the constructional space between the locking bars  16  and the first fitting part  11  and in the present case is located fixedly in terms of rotation on the eccentric  27 . The control disk  36  has—in the present case four—control tracks which in each case cooperate with a projection  38  of each locking bar  16 . The projections  38  in this case protrude in the axial direction from the locking bars  16  assigned thereto. With a rotation (by a few degrees) of the drive element  21 —and the eccentric  27  and the control disk  36  driven thereby—counter to the force of the spring  35 , the control disk  36  pulls the locking bars  16  radially inward, i.e. out of the toothed ring  17 , whereby the fitting  10  is unlocked and the two fitting parts  11  and  12  are able to be rotated relative to one another about the axis A. The backrest  4  is now able to be pivoted about the axis A in order to adjust its inclination, i.e. to adopt a further position of use. 
         [0054]    The closing direction c of the eccentric  27  is the direction of rotation of the eccentric  27  acting in the closing direction due to the action of the spring  35 . Hereinafter, the cooperation of one of the first eccentric cams  28  with the associated first locking cam  16   a  is considered, wherein the closing direction c in the figures is in the clockwise direction. In the present case, the remaining first eccentric cams  28  cooperate in a similar manner with the first locking cams  16   a  associated therewith. In a modification of the exemplary embodiment, however, only one first eccentric cam  28  is correspondingly configured. 
         [0055]    In the locked state and without additional loading of the backrest  4  (i.e. without external torque and only with the torque required by the weight of the backrest  4 ) the eccentric  27  acts on the locking bars  16  only by means of the first eccentric cams  28  which in each case act on the associated first locking cams  16   a  and namely in a first contact point K 1  (at which the first eccentric cam  28  and the first locking cam  16   a  are in contact with one another), whilst between the second eccentric cams  29  and the respectively assigned second locking cams  16   b  a gap exists of approximately 0.05 to 0.5 mm, preferably approximately 0.25 mm. 
         [0056]    If in the locked state a load acts on the backrest  4 , the resulting torque attempts to rotate the toothed ring  17  relative to the guide segments  14 . The locking bars  16  are guided with clearance between the guide segments  14  and, on the one hand, are in engagement with the toothed ring  17  and, on the other hand, supported on the associated first eccentric cam  28 . The torque on the backrest  4 , therefore, tilts the locking bars  16 , which are slightly movable due to the clearance, between and relative to the guide segments  14 . 
         [0057]    If the torque (relative to  FIGS. 7 to 9 ) acts counterclockwise on the upper locking bar  16 , the locking bar  16  tilts to the left (and comes into contact with the left-hand guide segment  14 ). The resulting force in the first contact point K 1  is increased. If the torque acts clockwise on the backrest  4  (in the figures), the locking bar  16  tilts to the right (and comes into contact with the right-hand guide segment  14 ). If the torque on the backrest  4  is sufficiently great, for example more than 100 Nm, the second eccentric cam  29  and the second locking cam  16   b  come into contact with one another at a second contact point K 2 . 
         [0058]    The situation relative to the tilting of the locking bar  16  on the diagonally opposing locking bar  16  is preferably as described before. In the locking bars  16  arranged adjacent therebetween, a mirror-inverted situation occurs relative to the closing direction c, i.e. these locking bars  16  tilt in the opposing direction and the associated first eccentric cams  28  lead in the closing direction c. In this case, —as is visible in  FIG. 5  —over the eccentric periphery, two first eccentric cams  28  and two second eccentric cams  29  are always located adjacent to one another. In a modification of the exemplary embodiment, however, the adjacent locking bars may also have the same layout, so that a locking bar is tilted in the same direction and over the entire eccentric periphery in each case a first eccentric cam  28  and a second eccentric cam  29  are alternately located adjacent to one another. 
         [0059]    The first eccentric cam  28  is subdivided along its outer contour into a plurality of cam portions of different geometry. Depending on the angular position of the eccentric  27 , one or more of these cam portions of the first eccentric cam  28  comes into contact with the first locking cam  16   a  at a first contact point K 1 . The individual cam portions are separated from one another in the peripheral direction, i.e. in the direction about the axis A through the following described (limit) points. In the axial direction (in the direction of the axis A) the cam portions preferably extend over the entire component width of the eccentric  27 . In the eccentric  27  of planar configuration, the component width of the eccentric  27  is defined by the material thickness thereof. 
         [0060]    The view counter to the closing direction c starts with a first cam portion  28 . 1  of the first eccentric cam  28  with a control contour which is defined by a rounded portion of a first flank of the eccentric cam  28  extending in the radial direction with the contour of the eccentric cam  28  extending in the peripheral direction and which controls the introduction of the locking bar  16  into the toothed ring  17 , by the first locking cam  16   a  cooperating with this control contour, when the locking bar  16  falls into the toothed ring  17 . The first cam portion  28 . 1  extends as far as a first point P 1  when viewed counter to the closing direction c. In a modification of the exemplary embodiment, the first cam portion  28 . 1  may be dispensed with, by the first flank of the eccentric cam  28  extending in the radial direction being connected to the contour of the eccentric cam  28  extending in the peripheral direction with sharp edges. 
         [0061]    A second cam portion  28 . 2  extends between the first point P 1  and a second point P 2  located relative to the first point P 1  counter to the closing direction c, said second cam portion being characterized by a cam contour extending on each point of the second cam portion  28 . 2  exactly in the peripheral direction, i.e. which extends exactly concentrically about the axis A, in other words with a wedge angle of 0° relative to the peripheral direction (zero degree contour). 
         [0062]    A normal force transmitted from the first locking cam  16   a  to the second cam portion thus passes through the central point of the fitting  10 , i.e. through the axis A, so that an opening moment does not act on the eccentric  27 . The length of the second cam portion  28 . 2  corresponds to an angular portion of the eccentric of ca. 1.5°. This corresponds to approximately 5% of the entire eccentric actuating angle of 30°. A reduction in the length of the second cam portion  28 . 2  to approximately 0°(line contact) is possible in theory. An increase is possible if desired but leads to correspondingly increased actuating angles and actuating energy when unlocking the fitting  10 . 
         [0063]    A third cam portion  28 . 3  extends between the second point P 2  and a third point P 3  located relative to the second point P 2  counter to the closing direction c, said third cam forming a continuous transition to a fourth cam portion  28 . 4 . 
         [0064]    The fourth cam portion  28 . 4  extends between the third point P 3  and a fourth point P4 located counter to the closing direction c, said fourth cam portion being characterized by a cam contour extending slightly radially outwardly relative to the peripheral direction—viewed counter to the closing direction c—which extends in a wedge angle, in the present case 4° to 6°. The closing direction c indicates how this wedge angle is measured. The wedge angle is positive, i.e. as viewed in the drawings, the regions of the fourth cam portion trailing in the closing direction c protrude further radially outwards than the leading regions so that the locking bar  16  acted upon by the first eccentric cam  28  may be locked and at the same time a compensation of tolerances is possible by a clearance being produced between the first eccentric cam  28  and the first locking cam  16   a  and/or between the toothing of the locking bar  16  and the toothed ring  17  by a wedge action. 
         [0065]    In a modification of the exemplary embodiment, the third cam portion  28 . 3  is dispensed with. The second cam portion  28 . 2  and the fourth cam portion  28 . 4  are thus located immediately adjacent to one another. This is possible without functional drawbacks, in particular with small wedge angles of the fourth cam portion  28 . 4 . 
         [0066]    A resulting force transmitted from the first locking cam  16   a  to the fourth cam portion  28 . 4  acts in an opening manner on the eccentric  27  but is compensated in a self-locking manner by the friction between the first eccentric cam  28  and the first locking cam  16   a.    
         [0067]    Viewed counter to the closing direction c, behind the fourth point P 4 , the cam contour preferably merges with a radius into the second flank of the first eccentric cam  28 . 
         [0068]    After mounting the fitting  10  a functional test is carried out, in which the important features for assessing the function and safety of the fitting  10  are tested. An important feature is the angular position of the drive element  21  which corresponds to the angular position of the eccentric  27  connected to the drive element  21 . The angular position of the drive element  27  corresponds to the actuating angle of the fitting  10  and provides information about the degree of locking of the fitting. 
         [0069]    In  FIGS. 7 to 9 , the angular position is shown of the eccentric depending on component tolerances.  FIG. 7  shows a locked fitting with components of nominal size. An eccentric angle of nominal size in the closing direction c is measured and in the present case is defined as the angle between, on the one hand, a line from the axis A to the radially extending central line of the locking bar  16  and, on the other hand, a line from the axis A through any measuring point but clearly defined on the second eccentric cam  29  located closest in the closing direction c. The first contact point K 1  between the first locking cam  16   a  and the first eccentric cam  28  is located on the fourth cam portion  28 . 4  (between the third point P 3  and the fourth point P 4 ). 
         [0070]      FIG. 8  shows a view corresponding to  FIG. 7  of a locked fitting with components subjected to tolerance, the tolerances thereof adding up to a maximum permitted overall tolerance acting on the eccentric angle of the eccentric  27 . Such overall tolerance results, for example, from a combination of a toothed ring  17  with a diameter which is too small, of a locking bar  16  having a nominal size and an eccentric  27  with an external diameter which is too large in the region of the first eccentric cams  28 . The eccentric  27  is then not able to rotate fully in the closing direction c so that the eccentric angle relative to the eccentric angle of nominal size of a fitting  10  with components of nominal size is smaller by ca. 4°. The first contact point K 1  between the first locking cam  16   a  and the first eccentric cam  28 , therefore, is located in the third cam portion  28 . 3  (between the second point P 2  and the third point P 3 ) or in the second cam portion  28 . 2  (between the first point P 1  and the second point P 2 ). In loaded conditions, which could lead to an opening of the eccentric  27  without the second cam portion  28 . 2 , optionally after slight rotation counter to the closing direction c, the eccentric  27  would remain in a position in which the first contact point K 1  might be in the second cam portion  28 . 2 . A further rotation of the eccentric  27  does not take place as, due to the contour of the second cam portion  28 . 2  extending concentrically about the axis A (zero degree contour), a force transmitted in the second cam portion  28 . 2  from the first locking cam  16   a  to the first eccentric cam  28  does not have an opening force direction. 
         [0071]      FIG. 9  shows a view corresponding to  FIG. 7  of a locked fitting  10  with component tolerances which are slightly too large and thus inadmissible. The first contact point K 1  (between the first locking cam  16   a  and the first eccentric cam  28 ), viewed in the closing direction c, is located in front of the second cam portion  28 . 2 . The eccentric angle relative to the eccentric angle of nominal size of the components of nominal size is smaller by ca. 7°. This angular difference may be established reliably during the mounting process by measurement technology, so that a fitting  10  with component tolerances which are too great may be rejected. As the second cam portion  28 . 2  has a wedge angle of 0° relative to the peripheral direction, the angular deviation of the eccentric angle from the (nominal) eccentric angle is greater than in a fitting with an eccentric without a zero degree contour, in which the wedge angle remains constant even when exceeding the tolerance limit, and exceeding the tolerance limit only results in a very slight angular deviation from the eccentric angle of nominal size. Exceeding the tolerances, therefore, by means of the zero degree contour of the second cam portion  28 . 2  between the first point P 1  and the second point P 2  may be identified easily. 
         [0072]    In a second exemplary embodiment shown in  FIGS. 10 to 12 , the fitting  10  is a freely pivoting fitting of the fitting system, which additionally has a counter fitting. Such a fitting system is disclosed, for example, in DE 20 2010 015 093 U1. The second exemplary embodiment corresponds substantially to the first exemplary embodiment, which is why only the differences are explained hereinafter. Components which are different from the first exemplary embodiment bear reference numerals increased by 100. 
         [0073]    The (freely pivoting) fitting  10  which is actuated via a second hand lever  6  serves together with the counter fitting for locking the free pivoting of the backrest  4 . In two-door motor vehicles, the access to a rear seat row is intended to be facilitated by means of the free pivoting of the backrest  4 , for which the unlocked backrest  4  is pivoted from one of the positions of use to the front into a freely pivoted position which is not suitable for seating use. It increases the ease of operation if the second hand lever  6  does not have to be held during the entire free pivoting movement, whilst the fittings are only locked in the freely pivoted position. To this end, in the (freely pivoting) fitting  10  an annular freely pivoting control element  45  is provided between the control disk  36  and the first fitting part  11  about the axis A, said annular freely pivoting control element being connected fixedly in terms of rotation to the first fitting part  11 . The freely pivoting control element  45  has stop tracks which cooperate with lugs  38  of the locking bars  16 , by limiting the movement of the locking bars  16  radially outwardly or permitting said locking bar to fall unhindered into the toothed ring  17  depending on the angular position of the freely pivoting control element  45 . 
         [0074]    The eccentric  127  of the fitting  10  in the unlocked state is rotated sufficiently far counter to the closing direction c that the first and/or second locking cams  16   a ,  16   b  of the locking bars  16 , pulled radially inwardly, are located in the intermediate spaces between the side contours of the first and second eccentric cams  128 ,  129  extending in the radial direction. The stop tracks of the freely pivoting control element  45  hold the locking bars  16  pulled inwardly, provided the backrest  4  is not pivoted back. The eccentric  127  is prevented from rotating by at least one of the first and/or second eccentric cams  128 ,  129  bearing in the peripheral direction on at least one of the first and/or second locking cams  16   a ,  16   b.    
         [0075]    The (freely) pivoting fitting  10  has means by which the fitting  10  and the counter fitting may be operatively connected together, in particular by means of a Bowden cable. The unlocked (freely) pivoting fitting  10  keeps the additionally unlocked counter fitting in the unlocked position. Relative to the first eccentric cam  28  of the first exemplary embodiment, between the first cam portion  28 . 1  and the second cam portion  28 . 2  the first eccentric cam  128  has an additional cam portion  128   z  arranged between an additional point P 100  and the first point P 1 , which—viewed counter to the closing direction—preferably has a cam contour which extends slightly radially outwards relative to the peripheral direction. Due to the additional cam portion  128   z  the width of the first eccentric cam  128  in the peripheral direction is larger than the width of the first eccentric cam  28  of the first exemplary embodiment (and larger than the width of the first eccentric cam of the counter fitting). 
         [0076]    Tolerances in the fitting system, for example a loose portion in the Bowden cable between the (freely pivoting) fitting  10  and the counter fitting are compensated by the additional cam portion  128   z  of the first eccentric cam  128  by the open eccentric  127  having a larger retaining angle due to the wider first eccentric cam  128 . The retaining angle describes the angle of the eccentric  127  about the axis A between the locked position and the position of the eccentric  127  held open by the bearing of the first and/or second locking cams  16   a ,  16   b  on the first and/or second eccentric cams  128 ,  129 . 
         [0077]    In the second exemplary embodiment the second eccentric cams  129  also have such an additional cam portion. 
         [0078]    The features disclosed in the above description, the claims and the drawings may be significant both individually and in combination for implementing the invention in its different embodiments. 
         [0079]    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.