Abstract:
A longitudinal adjuster, in particular for a vehicle seat, has at least one first seat rail ( 2 ) and, at least one second seat rail ( 3 ) which is arranged in a manner such that it can be displaced in a sliding manner relative to the first seat rail ( 2 ), and at least one end stop ( 11, 21, 31, 41, 51 ) which is attached to the first seat rail ( 2 ) and limits the relative displaceability of the two seat rails ( 2, 3 ) to each other by means of interaction with a second end stop ( 3   a ) which is formed by the second seat rail ( 3 ) or is attached to same. The first seat rail ( 2 ) is provided with at least two apertures ( 2   e ) through each of which protrudes a region of the end stop ( 11, 21, 31, 41, 51 ) serving to limit the seat rail movement in the longitudinal direction of the seat rails ( 2, 3 ), and the region is formed by a respective tab ( 11   a,    21   a   , 31   a   , 41   a   , 51   a ); formed integrally with the end stop ( 11, 21, 31, 41, 51 ). The associated aperture ( 2   e ) is formed in each case by a slot ( 2   e ) in the first seat rail ( 2 ), and the two tabs ( 11   a   , 21   a   , 31   a   , 41   a   , 51   a ) are arranged at the same height in the longitudinal direction of the seat rail ( 2 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a United States National Phase application of International Application PCT/EP2009/001312 and claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2008 012 888.0 filed, Mar. 6, 2008 the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a longitudinal adjuster with at least one end stop, in particular for a vehicle seat with at least one first seat rail and at least one second seat rail which is arranged in a manner such that it may be displaced in a sliding manner relative to the first seat rail. 
     BACKGROUND OF THE INVENTION 
     A longitudinal adjuster for a vehicle seat is known from DE 102 36 067 B4, with a first seat rail, to which first stop surfaces are associated, and a second seat rail displaceable in a sliding manner relative to the first seat rail, to which second stop surfaces are associated, the first stop surfaces and the second stop surfaces cooperating for limiting the relative motion of the second seat rail to the first seat rail. The first seat rail is connected at fastening points to the vehicle structure. For reinforcement at these fastening points and as an end stop during the displacement of the second seat rail, two stop plates of elongate configuration are provided. These stop plates respectively have four screw holes with internal threads arranged in series in the longitudinal direction of the rails, of which two are configured as through-holes, which face into the interior of the profile formed by the two seat rails. Along the two longitudinal edges, tabs are formed on the stop plates, which have first stop surfaces on the front face aligned in the longitudinal direction of the rails. On the second seat rail, an engagement part is arranged, the second stop surfaces being arranged on the engagement part. The engagement part reinforces the mutual interlocking of the two seat rails. In the longitudinal adjuster, the first stop surfaces are arranged on a stop plate connected to the first seat rail at fastening points, the stop plate being able to be selected from a set of different stop plates, and being able to be attached at different orientations relative to the longitudinal direction of the rails. 
     DE 198 04 506 C2 discloses an end stop for limiting the regulating distance of a longitudinal adjustment device for seats. The seat part of the seat is in this connection fastened to slide rails, each slide rail being longitudinally displaceable in a guide rail secured to the vehicle floor and at least one slide rail being able to be secured by means of a locking device in selectable longitudinal positions on the guide rail. In this connection, an end stop is provided between the slide rail and the guide rail. To provide a resilient energy-absorbing end stop, and to avoid production processes for the mounting of the end stop, said end stop is formed by an impact element with a snap-in head, penetrating an aperture of the guide rail, and a locking hook penetrating said impact element and latching onto the guide rail. 
     A longitudinal adjuster for a vehicle seat is further known from DE 10 2005 012 018 A1, with at least one first seat rail, at least one second seat rail, which is arranged in a manner such that it may be displaced in a sliding manner relative to the first seat rail, and at least one end stop, which is attached to the first seat rail, and limits the relative displaceability of the two seat rails to one another by means of interaction with a second end stop, which is formed by the second seat rail or attached thereto, the end stops being arranged in the interior of an assembled hollow profile formed by the seat rails. In this connection, a plurality of apertures are provided in the seat rail, into which protruding regions of the end stop engage, at least one of the protruding regions which engage in an aperture, protruding through the aperture, and by means of the protruding region, by interaction with the second end stop, limiting the seat rail movement in the longitudinal direction of the seat rails. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to improve a longitudinal adjuster of the aforementioned type. 
     The invention relates to a longitudinal adjuster, in particular for a vehicle seat, with at least one first seat rail, at least one second seat rail which is arranged in a manner such that it may be displaced in a sliding manner relative to the first seat rail, and with at least one end stop which is attached to the first seat rail and limits the relative displaceability of the two seat rails to each other by means of interaction with a second end stop which is formed by the second seat rail or is attached thereto. In this connection, a plurality of apertures is provided in the seat rail, into which protruding regions of the end stop engage, at least two apertures being provided, through each of which protrudes a protruding region of the end stop, serving to limit the seat rail movement in the longitudinal direction of the seat rails. The protruding regions of the end stop, which protrude through the apertures and limit the rail movement in the longitudinal direction of the seat rails, are thus arranged at the same height in the longitudinal direction of the seat rail. 
     The protruding region is preferably formed by one respective tab formed integrally with the end stop, the associated aperture is formed in each case by a slot in the first seat rail, and the two tabs are arranged at the same height in the longitudinal direction of the seat rail. As the end stop is attached from the outside to one of the seat rails, in particular the lower rail, if required a retrospective assembly is also possible, in particular a repair may be carried out from outside relatively easily. In particular, in the case of damping elements which may be arranged on the end stop, and which wear over time, a replacement of the corresponding end stops is thus possible. Moreover, as a plurality of apertures is provided in the seat rail, not all of which are used, an adjustability of the end stop during assembly or possible retrospective attachment may be provided. In particular, the stops may be assembled at a later time than is otherwise usual, for example in a just-in-time plant or directly at the automobile manufacturer. The seat rails together with the end stops may be used for different vehicles, with different requirements, in particular different adjustment lengths of the seat. 
     The provision of two protruding regions, in particular tabs, which may come to bear against two corresponding regions of the second end stop, distributes the forces which occur in the event of a movement of the seat rails into the end position, onto two partial regions. These partial regions are particularly preferably arranged mirror symmetrically to the central longitudinal line of the rails. In particular, in the region of the central longitudinal line further means for force transmission, such as fastening means (for example rivets, screws, or the like) or projections, which protrude in corresponding openings of the other component are preferred. 
     The end stop is preferably of T-shaped configuration, the ends of the crossbar being bent in one direction by an angle of 45° to a maximum of 135°, in particular preferably 60° to 90°, relative to the longitudinal member of substantially planar configuration, and form tabs which protrude through apertures in the first seat rail and one respective lateral region of the tabs protruding through the apertures interacts with the second end stop. 
     Quite particularly preferably, the ends of the crossbar are bent in one direction by 75° or 90° relative to the longitudinal member of substantially planar configuration, tolerances of up to +/−10° being able to occur as a result of production. By means of an embodiment with tabs bent upwards by 75°, the end stop has an improved strength, by means of an embodiment with tabs bent upwards by 90°, the slots in the corresponding rail may be kept narrower and the assembly is somewhat simplified. 
     In particular, a projection and an opening are preferably configured along the central longitudinal line of the longitudinal member. The projection is preferably used in this connection for pre-positioning. The opening serves for subsequent fixing of the end stop to the rail by means, for example, of a blind rivet in addition to fixing the correct alignment of the end stop-longitudinal member parallel to the rail longitudinal axis. 
     Preferably the opening is arranged centrally between the tabs. In particular, the opening is preferably arranged along the central longitudinal line of the seat rail. 
     The end stop has preferably at least one projection which is positioned in an aperture configured in the first seat rail, in particular an oblong hole or an opening, and with one region bears against the edge region of the aperture. 
     Preferably, the end stop has at least one notch, which interacts with an edge region of an aperture in the first seat rail, in particular keeps the end stop in abutment against the seat rail, in the end position and/or during a pivoting movement in the course of assembly. 
     In particular, the end stop preferably has insertion aids. The insertion aids are particularly preferably formed by regions of the tabs which are of curved configuration, protruding in the insertion direction. These regions of the tabs of curved configuration may simply be inserted in slots configured in the first seat rail, the alignment of the end stop being oblique relative to the seat rail. After complete insertion, a pivoting motion takes place by which the seat rail and end stop are brought to lie flat against one another. In this connection, a projection which engages in an opening of the seat rail preferably ensures the correct position of the end stop relative to the seat rail. 
     Alternatively, after inserting the insertion aids and a pivoting motion in which an edge region of the rail is positioned in the notch, after reaching a position which is still slightly oblique relative to the first seat rail, a sliding motion may be provided, by which the notch is brought out of engagement with the edge region and the side of the tab opposing the notch is brought to bear against the opposing edge region. As a result of the return movement, the projection and opening are aligned with one another, so that the end stop may be moved into its end position. 
     After the positioning has taken place, a fastening of the end stop to the seat rail takes place particularly preferably by means of a blind rivet, which may be attached from outside. 
     For reducing noise, on the end stop at least one resiliently deformable damping element is particularly preferably provided in the region of the surface coming into contact with the second end stop. This damping element damps the impact of the end stops and prevents the striking of metal on metal. The damping element may, for example, be formed by coating the end stop with a resilient material. Also, an attachment of a damping element of block-like or cylindrical configuration is possible on the surfaces which come into contact with the other end stop. The attachment may take place in any manner, for example by means of bonding, clipping, pushing-on or insertion into a correspondingly configured receiver region. 
     The end stop is particularly preferably formed by a stamped and bent part made of metal, which may be produced easily and cost-effectively. However, other suitable materials are also possible, such as for example a plastics material which is sufficiently hard and has a sufficient load-bearing capacity. In the case of an embodiment as a plastics component, a damping element may be directly injection-molded in a two-component injection-molding method. 
     Particularly preferably, the maximum regulating distance, which is limited by fixed end stops provided on the seat rails, may be additionally limited by the end stops according to the invention, in particular preferably directly in the factory of the automobile manufacturer, so that an adaptation to different vehicle series is possible on site. Thus the fixed end stops provided on the seat rails provide an additional safety mechanism against a release of the seat rails if, for example, during assembly in the factory of the automobile manufacturer the variable end stop had been inadvertently forgotten. 
     The invention is described in more detail hereinafter with reference to a plurality of embodiments shown in the drawings. 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 
       In the drawings: 
         FIG. 1  is a perspective view from below of a lower rail with two fitted stops according to the first embodiment; 
         FIG. 2  is a further detailed perspective view of the lower rail with an end stop of  FIG. 1 ; 
         FIG. 3  is a view from below of the lower rail together with stops of  FIG. 1 ; 
         FIG. 4  is a section along the line IV-IV of  FIG. 3 ; 
         FIG. 5  is a detailed view in the direction of the arrow V of  FIG. 4 ; 
         FIG. 6  is a perspective view of an end stop according to the first embodiment; 
         FIG. 7  is a section in the longitudinal direction through the end stop of  FIG. 6 ; 
         FIG. 8  is a detailed, schematic drawing of the assembly of the lower rail, end stop and upper rail according to the first embodiment; 
         FIG. 9  is a perspective view of a lower rail without stops according to the second embodiment; 
         FIG. 10  is a perspective detailed view of the lower rail of  FIG. 9  with two stops; 
         FIG. 11  is a perspective detailed view of a lower rail with an end stop according to the third embodiment after insertion and before assembly; 
         FIG. 12  is a view corresponding to  FIG. 11  after assembly and before riveting; 
         FIG. 13  is a perspective detailed view of a lower rail with an end stop according to the fourth embodiment in a first step of the assembly; 
         FIG. 14  is the lower rail with the end stop of  FIG. 13  in a second step of the assembly; 
         FIG. 15  is the lower rail with the end stop of  FIG. 13  after the assembly and riveting has been completed; 
         FIG. 16  is a schematic side view of a vehicle seat with the vehicle structure indicated; 
         FIG. 17  is a perspective view of an end stop according to the fifth embodiment; and 
         FIG. 18  is a front view of the end stop of  FIG. 17 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings in particular, a vehicle seat  1  shown schematically in  FIG. 16  for a motor vehicle has two first seat rails, also denoted hereinafter as lower rails  2 , which are fixedly connected at fastening points to the vehicle structure, two second seat rails, also denoted hereinafter as upper rails  3 , which are arranged in a manner such that they may be displaced in a sliding manner relative to the respectively associated first seat rail, and a seat part  4  with a backrest  5  which are arranged on the second seat rails and thus displaceably relative to the first seat rails. Via structures and adjustment devices (not shown) known per se, the seat height, seat inclination and backrest inclination may be adjusted in a manner known per se. Moreover, the seat position may be adjusted in the longitudinal direction of the vehicle by a further adjustment device, by displacing the second seat rails relative to the first seat rails, corresponding latching devices (not shown) being provided for fixing the respectively desired position of the seat rails to one another. For limiting the longitudinal displacement of the seat rails relative to one another stops are respectively provided, about which further details will be provided during the course of the subsequent description of the individual embodiments. 
     Due to the embodiment of the seat rails of the seat rail pairs which are configured to be substantially mirror symmetrical, as well as the corresponding stops between the first and second seat rails in both directions of the longitudinal displaceability, the invention is described hereinafter in more detail with reference to the description of an end stop, the construction of the vehicle seat  1  apart from the stops and the corresponding adaptations of the seat rails, insofar as they are not explained below in detail, being consistent in all embodiments. 
     Moreover, in all embodiments described hereinafter, the first seat rail or lower rail  2  is formed by a U-shaped profile, in which the edges are bent back twice inwards. The second seat rail or upper rail  3  is mounted therein, it also being formed by a U-shaped profile, in which however an edge region is bent back outwards, so that the end is positioned in the edge region of the first seat rail, viewed in the longitudinal direction of the second seat rail, a part (not shown) being bent back further so that said part is arranged within the edge which has been bent back twice, and a part forming an end stop  3   a  of the second seat rail, having a greater height relative to the base of the second seat rail and additionally only being bent outwards by approximately 90° (see  FIG. 8 ). 
     In the region of the surfaces of the end stops in contact with one another, to reduce noise, although not expressly mentioned below, a damping element may be attached to one or both end stops, in particular made of a resilient plastics material. The attachment may be carried out in any manner, for example by bonding on a buffer or partially coating the base body forming the end stop. 
     The first seat rail is positioned in a manner known per se by means of a centering pin arranged on the vehicle structure, which is guided through a centering opening  2   a , having a circular cross section, of the seat rail and serving as centering aid, and in the present case fixed by means of two screws which are inserted through two fastening openings  2   b , having a circular cross section, of the seat rail, and screwed in the vehicle structure. The fastening may, however, also take place in any other suitable manner. 
     First Embodiment 
     According to the first embodiment an end stop  11 , which is formed by a T-shaped stamped and bent part made of sheet metal, is attached to a lower rail  2 . In this connection, as is visible from  FIG. 6 , the two opposing ends, also denoted as tabs  11   a , of the crossbar are bent upwards at an angle of 90°. In the longitudinal member, approximately between the tabs  11   a , are formed an opening  11   b  with a circular cross section and in the other part of the longitudinal member a cam-like projection  11   c  with a circular cross section, which projects in the same direction as the tabs  11   a , the opening  11   b  and projection  11   c  being located in the central longitudinal line of the longitudinal member. 
     For attaching the end stop  11  in a position which meets requirements, in the longitudinal direction of the lower rail  2  a plurality of openings  2   c  with circular cross sections and oblong holes  2   d  are provided on said lower rail along the central longitudinal line thereof and slots  2   e  are provided on both sides of the openings  2   c , an opening  2   c , an oblong hole  2   d  and two slots  2   e  arranged on both sides of the opening  2   c  respectively securing a possible position of the end stop  11 . The internal diameter of the opening  2   c  corresponds substantially to the internal diameter of the opening  11   b  of the end stop  11 . The width of the oblong holes  2   d  corresponds substantially to the diameter of the cam-like projection  11   c  of the end stop  11 , the width of the oblong holes  2   d  being slightly greater than the diameter of the projection  11   c . The slot lengths of the slots  2   e  in the lower rail  2  correspond substantially to the widths of the tabs  11   a , the slot lengths of the slots  2   e  being slightly greater than the widths of the tabs  11   a , the widths of the slots  2   e  however, corresponding substantially to the thickness of the tabs  11   a.    
     The tabs  11   a  of the end stop  11  are placed in the desired position of the end stop  11  relative to the lower rail  2  through two opposing slots  2   e  arranged accordingly in the lower rail  2 , and the projection  11   c  of the end stop  11  is positioned in an adjacently arranged oblong hole  2   d , a simple assembly being possible by the oversize of the openings relative to the regions arranged therein. By the corresponding design of the arrangements of the openings and oblong holes in the lower rail  2  the correct installation direction of the end stop  11  is ensured. The insertion of a blind rivet  12  in the opening  2   c  of the lower rail  2 , which is aligned with the opening  11   b , fixes the final position of the end stop  11  on the lower rail  2 , and this position is secured by the riveting of the blind rivet  12 . 
     Second Embodiment 
     According to the second embodiment which, provided it is not described hereinafter, corresponds to the first embodiment, second openings  2   d ′ with circular cross section are provided on the lower rail  2  in place of the oblong holes  2   d . In this connection, the openings  2   c , hereinafter denoted also as first openings to differentiate from the second openings  2   d ′, are arranged centrally between a pair of slots  2   e , and the first and second openings  2   c  and  2   d ′, which respectively have the same internal diameter, are arranged centrally along the central longitudinal line of the lower rail  2  continuously and at uniform intervals from one another. 
     The end stop  21  according to the second embodiment is configured corresponding to the end stop  11  of the first embodiment, so that relative thereto reference is made to the views of  FIGS. 6 and 7 . The end stop  21  is fixed to the lower rail  2 , corresponding to the end stop  11  of the first embodiment by means of a blind rivet  22 , which corresponds to the blind rivet  12  of the first embodiment, which is guided through the openings  2   c  and  21   b  aligned with one another. The projection  21   c  is arranged within one of the openings  2   d′.    
     As a result of the continuous arrangement of the openings  2   c  and  2   d ′ as well as the slots  2   e  over the length of the lower rail  2  as well as the corresponding embodiment of the end stops  21 , the end stops  21  may be inserted at a plurality of positions located, in particular, equidistant relative to one another, in the longitudinal direction of the lower rail  2  and inserted into the lower rail  2  oriented in both directions and fixed thereto. 
     Third Embodiment 
     The third embodiment corresponds to the first embodiment, provided it is not described otherwise below. Thus the lower rail  2  again has along the central longitudinal line a plurality of openings  2   c  with circular cross sections and oblong holes  2   d  as well as slots  2   e  on both sides of the openings  2   c , an opening  2   c , an oblong hole  2   d  and two slots  2   e  arranged on both sides of the opening  2   c  respectively securing a possible position of the end stop  31 . The end stop  31  is also configured according to the end stop  11  of the first embodiment, but on the side of the tabs  31   a  more remote from the projection  31   c , in the transition region to the central part of the end stop  31  notches  31   a ′ are formed, the width thereof substantially corresponding to the material thickness of the lower rail  2 , and which serve for the additional locking of the end stop  31  to the rail  2  of the receiver of an edge region of the slots  2   e.    
     The assembly of the end stop  31  to the lower rail  2  is carried out by the tabs  31   a  being inserted level with the desired position of the end stop  31  on the lower rail  2  into the corresponding slots  2   e , until the projection  31   c  is positioned in the corresponding oblong hole  2   d , and the surfaces facing one another of the end stop  31  and lower rail  2  bear against one another. Subsequently, the end stop  31  is displaced in the longitudinal direction of the lower rail  2 , such that the projection  31   c , which is at one end of the corresponding oblong hole  2   d , and the notches  31   a ′ receive the corresponding edge regions of the slots  2   e . In this position, the openings  2   c  and  31   b  are aligned with one another. A blind rivet (not shown) is positioned and riveted through the openings  2   c  and  31   b  aligned with one another, so that the end stop  31  is fastened to the lower rail  2 . 
     Fourth Embodiment 
     The design of the lower rail  2  according to the fourth embodiment corresponds to that of the second embodiment, i.e. openings  2   c  and  2   d ′ are continuous along the central longitudinal line, and arranged at uniform intervals, one of the openings being arranged centrally between two slots  2   e , so that the end stops  41  may be attached again oriented in both directions. The end stop  41  corresponds, relative to the design of the central region, to the previously described end stops  11 ,  21  and  31 , but differs in the design of the tabs  41  thereof. Thus the tabs comprise notches  41   a ′ which correspond in their function to the notches  31   a ′ of the third embodiment. Additionally, however, insertion aids  41   a ″ in the form of claw-like projections are formed on the tabs  41   a  above the notches  41   a ′ and extending in the plane of the tabs  41   a , which extend on the side of the end stop  41  opposing the projection  41   c.    
     The assembly of the end stop  41  to the lower rail  2  takes place by the insertion aids  41   a ″ of the tabs  41   a  being inserted level with the desired position of the end stop  41  on the lower rail  2  in the corresponding slots  2   e , the end stop  41  being positioned obliquely to the lower rail  2  for the insertion (indicated by the arrow in  FIG. 13 ). With the bearing of the notches  41   a ′ on the corresponding edge regions of the slots  2   e , an alteration to the direction of movement takes place, namely the end stop  41  is now pivoted toward the lower rail  2  about an axis extending within the notches  41   a ′ (see curved arrow in  FIG. 14 ), until the end stop  41  is positioned approximately parallel with the lower rail  2 . Subsequently, the end stop  41  is again slightly moved back, so that on both sides the edge region of the slots  2   e  consisting of the notches  41   a ′ and on the opposing regions of the tabs  41   a  comes to bear against the opposing edge region of the slots  2   e . Subsequently, the end stop  41  is moved in the direction of the lower rail  2 , until the projection  41   c  of the end stop  41  is positioned in the corresponding opening  2   d ′ and the surfaces facing one another of the end stop  41  and the lower rail  2  bear against one another. In this position, the opening  2   c  and the corresponding opening in the end stop  41  are aligned with one another. A blind rivet  42  is positioned and riveted through the openings aligned with one another, so that the end stop  41  is fastened to the lower rail  2 . 
     In all the embodiments described above, the support of the projection and oblong hole and/or opening as well as the support of a part of the side surfaces of the tabs on corresponding edge regions of the slots form an additional support to the support formed by the blind rivet. Moreover, by the use of a rivet in a region of openings of corresponding dimensions aligned with one another, which are arranged without any spacings between one another, the loading of the rivet is kept as low as possible. 
     Moreover, in the present case the end stops are arranged according to all embodiments such that the crossbars of the T-shaped end stops, the blind rivets also being arranged in the region thereof, are located on the side facing one another (see, for example FIG.  1 ).\ 
     The regions, which are in contact with the end stop  3   a  of the upper rail  3 , are located in all embodiments on the underside of the crossbar of the T-shaped end stops, so that the upper face of the crossbars or the corresponding notches are pressed therein against the edge regions of the slots  2   e  in the lower rail  2 . In the case of the end stops of the upper and lower rail striking one another, the lower part of the longitudinal member is pressed against the surface of the lower rail  2  and thus the projection of the end stop in the corresponding aperture (circular opening  2   d ′ and/or oblong hole  2   d ) so that additionally the loading of the blind rivet is kept low. 
     Fifth Embodiment 
     According to the fifth embodiment of a longitudinal adjuster, only the design of the end stop  51  differs substantially from that of the end stop  11  of the first embodiment. The design of the rails  2  and  3  corresponds to that of the first embodiment, but the slots  2   e  being configured slightly wider for the reception of the tabs  51   a  of the end stop  51 , as may be understood from the subsequent description of the end stop  51 . 
     The end stop  51  is again formed by a T-shaped stamped and bent part made of sheet metal. In this connection, as is visible from  FIGS. 17 and 18 , the two ends opposing one another, also denoted as tabs  11   a , of the crossbar are bent at an angle α of 75° upwards. In the longitudinal member, approximately between the tabs  51   a  an opening  51   b  with a circular cross section is formed and in the other part of the longitudinal member a cam-like projection  51   c  with a circular cross section is formed, which projects in the same direction as the tabs  51   a , the opening  51   b  and projection  51   c  being located in the central longitudinal line of the longitudinal member. The dimensions of the opening  51   b  and of the projection  51   c  correspond to those of the first embodiment. Similarly—according to the first embodiment—the widths of the crossbars and longitudinal members are approximately the same in the present case. By the smaller bending angle, by which the tabs  51   a  are bent up, the end stop  51  has an improved strength. Moreover, by the oblique path of the tabs  51   a  with an otherwise unaltered design, in particular with the same material thicknesses, as in an end stop  11  according to the first embodiment a slightly greater contact surface may be produced between the tabs  51  and the rail  3  than the contact surface between the tabs  51  and the rail  3  (see  FIG. 8 ) so that the loading of the end stop  51  and the rail  3  when in contact with one another may be slightly reduced relative to an end stop  11  according to the first embodiment. 
     The attachment and fixing of the end stop  51  to the rail takes place according to that of the end stop  11  according to the first embodiment, so that further details will not be provided about this. 
     Although not disclosed, in the presently described embodiments fixed end stops may be provided in addition to the end stops  11 ,  21 ,  31 ,  41 ,  51  attached to the seat rail. Said fixed end stops may, for example, be formed by corresponding, bent-back regions of the seat rail or by unreleasable parts fastened to the seat rail, which is why these fixed end stops may also be considered as fixed stops. The fixed stops define the relative movement of the seat rails to one another in a maximum displacement range. The end stops  11 ,  21 ,  31 ,  41 ,  51  additionally attached to the seat rail reduce this maximum displacement range to the displacement range which is ultimately desired. 
     While specific embodiments of the invention have been 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.