Abstract:
In a supplemental locking mechanism ( 11 ) for a longitudinal adjuster of a vehicle seat, in particular for a longitudinal adjuster of an automobile seat, wherein an upper rail ( 4 ) extends for sliding movement in a lower rail ( 5 ) and is adapted for being locked with same, the supplemental locking mechanism ( 11 ) being inactive in the normal case, and locking the upper rail ( 4 ) with the lower rail ( 5 ) only in the event of a crash. A part of a safety belt system is arranged on a belt adapter ( 12 ), which is secured to the upper rail ( 4 ), with the mounted component of the safety belt system moving in the event of a crash at least one part ( 12′″ ) of the belt adapter ( 12 ) in a defined manner relative to the upper rail ( 4 ) and to the lower rail ( 5 ), thereby engaging the supplemental locking device ( 11 ).

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a supplemental locking mechanism for a longitudinal adjuster of a vehicle seat, in particular for a longitudinal adjuster of an automobile seat.  
           [0002]    Longitudinal adjusters of vehicle seats must be dimensioned such that in the event of a crash, paired seat rails do not disengage and locking mechanisms do not open. Otherwise, the vehicle seat will separate from the vehicle structure, and accelerate in the event of a crash. In the case of vehicle seats with a manual lengthwise adjustability, it may further occur that shortly before a crash, the seat user has accidentally released the locking mechanism to readjust the vehicle seat. If a crash occurs, the vehicle seat will be accelerated likewise in this event. Due to the high relative speed, the locking mechanism will no longer be able to engage, even when the locking lever is let go. In this instance, the vehicle seat moves to its end stop and then abruptly stops, which may cause injuries to the seat user. For this reason, DE 35 36 545 A1 proposes to provide a supplemental locking mechanism with a crash-sensitive inertia pendulum as a triggering device. This solution is somewhat expensive in its manufacture, since a high sensitivity requires precision machining of the parts.  
         SUMMARY OF THE INVENTION  
         [0003]    In accordance with one aspect of the present invention, an improved supplemental locking mechanism is provided. In accordance with this aspect, the supplemental locking mechanism is for a vehicle seat that includes a safety belt system and a longitudinal adjuster, with the longitudinal adjuster having an upper rail mounted for moving relative to a lower rail and for being locked to the lower rail. Further in accordance with this aspect, the supplemental locking mechanism includes a belt adapter secured to the upper rail, and a component of the safety belt system is mounted to the belt adapter. More specifically, the belt adapter is operative to allow movement of the component of the safety belt system relative to the upper rail in the event of a crash. The belt adapter is additionally operative so that the movement of the component of the safety belt system causes at least one part of the belt adapter to move relative to the upper and lower rails as a result of the crash. The supplemental locking mechanism engages as a result of the movement of the part of the belt adapter. While engaged, the supplemental locking mechanism locks the upper rail to restrict movement of the upper rail relative to the lower rail. In contrast, the supplemental locking mechanism does not prevent movement of the upper rail relative to the lower rail absent a crash  
           [0004]    In the following, the term “locking” refers not only to a formfitting engagement, but also to a frictional engagement, if need arises. By mounting a component of a safety belt system to a belt adapter secured to the upper rail, with the mounted part of the safety belt system moving at least one part of the belt adapter in a definable manner relative to the upper and lower rails, and engaging the supplemental locking mechanism in the event of a crash, a supplemental locking mechanism with a very sensitive crash sensor is made available, which is simple and cost-favorable to make because of the use of already existing components. The defined movement of the belt adapter or of its part sees to a reliable engagement of the supplemental locking mechanism.  
           [0005]    Preferably the part of the belt adapter that is to be moved in the event of a crash is associated with a locking element. The locking element comes, as a result of the movement in the event of a crash, into contact with the lower rail or a component rigidly connected thereto, and cooperates with same while producing a formfitting engagement and/or a frictional engagement for purposes of locking. For a reliable transmission of force, the locking element is made preferably integral to the belt adapter, but may also be made separate and be separately supported, so long as it is rigidly connected to the belt adapter. For a simpler production and a better possibility of retrofitting, the part that is rigidly connected to the lower rail is made as a separate component. Before producing a formfitting and/or a frictional engagement for locking, a deformation of components of the supplemental locking mechanism may occur, which is used for degrading energy or for forming a part of the defined movement. The defined movement of the part of the belt adapter relative to the upper rail occurs in such preferred cases by means of deforming the belt adapter. This is followed by the engagement of the supplemental locking mechanism.  
           [0006]    In a preferred construction, the belt adapter includes a clamp, which surrounds the upper and the lower rails, and which is moved in the event of a crash. The complete or almost complete enclosure of the rails by the clamp provides for a better locking engagement in the event of a crash. When the clamp is made integral with the belt adapter, it is possible to make the belt adapter simply as a stamped and bent metal part. In the event of a crash, the clamp cooperates preferably with a deformable part rigidly connected to the lower rail, so that with the exception of energy degradation, there is still a proper formfitting engagement after the deformation. The clamp itself sees to a suitably shaped engagement with the lower rail. Preferably, the deformable part is designed and constructed as a locking brush with a plurality of projecting locking fingers. This locking brush extends along the lower rail over the entire possible path of travel of the clamp, and has good deforming capabilities. A deformability in sections exists in any possible longitudinal position of the seat, which increases safety.  
           [0007]    Suitable for the defined movement of the belt adapter or its part are, for example, a defined bending, or other deformation of the belt adapter, or a defined rotation, or sliding of the belt adapter. In the case of a defined rotation, the belt adapter is supported, for example, for rotation. During the normal use, it is secured in frictional engagement by a correspondingly great friction torque or spring force, or in formfitting engagement by a pin. In the event of a crash, the belt adapter will rotate only when the crash forces overcome the friction torque or spring force, or when they shear the pin. Stationary stops may limit the movement of the belt adapter or its part. In the case of a defined bending, an additional degradation of energy occurs. In the case of the defined rotation, it is possible to obtain advantageous force ratios by designing and constructing the belt adapter as a rotational lever.  
           [0008]    A vehicle seat of the present invention may include in its longitudinal adjuster a supplemental locking mechanism on only one seat side, preferably that with the belt buckle, or on each side of the seat, i.e., in addition on the side with the pelvic belt mount. It is also possible to retrofit finished vehicle seats with the supplemental locking mechanism of the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    Having thus described the invention in general terms, in the following, five embodiments of the present invention are described in greater detail with reference to drawings, in which:  
         [0010]    [0010]FIG. 1 is a perspective partial view, as seen obliquely from the front of seat rails, which are provided on the right side of the vehicle seat, according to a first embodiment;  
         [0011]    [0011]FIG. 2 is a bottom view corresponding to FIG. 1;  
         [0012]    [0012]FIG. 3 is a schematic side view of a vehicle seat according to the first embodiment;  
         [0013]    [0013]FIG. 4 is a side view corresponding to FIG. 1, as seen from the back without a rear foot;  
         [0014]    [0014]FIG. 5 is a schematic partial view of a second embodiment;  
         [0015]    [0015]FIG. 6 is a schematic partial view of a third embodiment;  
         [0016]    [0016]FIG. 7 is a schematic partial view of a fourth embodiment; and  
         [0017]    [0017]FIG. 8 is a schematic partial view of a fifth embodiment. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.  
         [0019]    In the first embodiment, a vehicle seat  1  for an automobile comprises a preferably manually actuatable longitudinal adjuster  3  with respectively an upper rail  4  integral with the seat structure and a lower rail  5  integral with the vehicle structure on both sides of the vehicle seat. The normal orientation of the vehicle seat  1 , which is designed and constructed as a driver seat, defines the directions indicated in the following. Each upper rail  4  extends for movement as a slide bar in the associated lower rail  5  serving as a guide rail for adjusting the longitudinal position of the seat in its longitudinal direction. The two rails  4  and  5  engage behind each other in a known manner. To secure the adjusted longitudinal position of the seat, the longitudinal adjuster  3  comprises a main locking mechanism (not shown). In the following, the otherwise symmetrically constructed longitudinal adjuster  3  is described for the sake of simplicity only in the rear region of the right side of the vehicle seat.  
         [0020]    In case of a crash, the longitudinal adjuster  3  is provided with a supplemental locking mechanism  11 , which includes a belt adapter  12  with a clamp  14  arranged at the rear end of upper rail  4 , and a locking brush  15  arranged at the rear end of lower rail  5 . The belt adapter  12 , which is made in one piece as a stamped and bent metal part, successively includes in the longitudinal direction of the rails (x-direction), an angular mounting section  12 ′, which is secured with one leg by means of two screws to upper rail  4 , a bending section  12 ″, which is a continuation of mounting section  12 ′ in two separated legs, and an angular adapter section  12 ′″, which adjoins bending section  12 ′, and to which a belt buckle  16  of a safety belt system is screwed.  
         [0021]    The clamp  14  made integral with belt adapter  12  in the form of a strip projects from adapter section  12 ′″ laterally inward, curves downward around upper rail  4 , bends around the bottom of lower rail  5  including locking brush  15  and a rear foot  17  serving for the mounting to the vehicle floor, and bends again upward around upper rail  4  toward the outer side of belt adapter  12 . The rear end of belt adapter  12  is arranged at a certain distance within a stop clamp  18  mounted to upper rail  4 .  
         [0022]    The locking brush  15  is made of an elongate metal sheet, which is slit several times on its two obliquely upwardly bent longitudinal sides, so that a plurality of locking fingers  15 ′ are formed as “bristles” of locking brush  15 . Together with rear foot  17 , the locking brush  15  is screwed to lower rail  5 . In the region of locking brush  15 , the lower rail  5  is spaced from the vehicle floor so far that during the normal longitudinal adjustment of vehicle seat  1 , it is possible to move clamp  14  unimpeded between locking brush  15  extending over its entire path of travel and the vehicle floor. The supplemental locking mechanism  11  is therefore inactive in the normal case.  
         [0023]    In the event of a crash, a relative movement between the seat user and vehicle seat  1  causes a pull in the safety belt, which pulls buckle  16  upward relative to upper rail  4 . Due to the great bending moment, the belt adapter  12  yields in the region of bending section  12 ″ in a predetermined defined manner, i.e., the belt adapter  12  bends in the z-direction such that mounting section  12 ′ remains in contact with upper rail  4 , while adapter section  12 ′″ moves upward. As a result, the clamp  14  is likewise pulled upward, so that corresponding to its width, it comes into contact with some locking fingers  15 ′, which are arranged within clamp  14  in the adjusted length position of the seat. Due to the great forces, the clamp  14  bends these locking fingers  15 ′ inward and comes in the longitudinal direction of lower rail  5  by way of a formfitting engagement into contact with adjacent locking fingers  15 ′.  
         [0024]    The upward movement of adapter section  12 ′″ and clamp  14  is limited respectively by the adapter section  12 ′″ coming into contact with stop clamp  18 , which forms an integral part of the upper rail, or by clamp  14  contacting the downward extending nonslitted portion of locking brush  15 . Depending on the magnitude of the crash forces, the vehicle seat  1  may still be caused to move in the longitudinal direction. During this movement, it is possible that the clamp  14  will break some locking fingers  15 ′. The bending of bending section  12 ″ and locking fingers  15 ′ causes energy to degrade to such a great extent that it prevents high acceleration peaks for the seat user.  
         [0025]    In a modified embodiment of the supplemental locking mechanism, a frictional engagement is produced instead of the formfitting engagement, for example, between the clamp and a correspondingly roughened underside of the lower rail.  
         [0026]    The embodiments two to five correspond substantially to the first embodiment. For this reason, reference numerals, each time increased by 100, have been selected for identical or identically acting components, and only differences are described in the following.  
         [0027]    The supplemental locking device  111  of the second embodiment comprises a belt adapter  112  in the form of a rotational lever, which is arranged on the upper side of upper rail  104  such that effective a certain torque, it rotates about the z-axis. In the event of a crash, this torque that engages the shorter lever arm, is applied by the force initiated via the belt buckle. As a result of the defined rotation of belt adapter  112 , the clamp  114  comes into contact with the side wall of lower rail  105 . Depending on the construction, a frictional engagement is produced, or, if the side wall of lower rail  105  includes a gear tooth section, as shown in phantom lines in FIG. 5, a formfitting engagement will be produced, which additionally locks the two rails  104  and  105 , respectively.  
         [0028]    In the third embodiment, the supplemental locking mechanism  211  likewise comprises a belt adapter  212  as a rotational lever arranged for rotation on upper rail  204 . However, unlike the second embodiment, it is rotatable about the y-axis. In the case of a correspondingly great torque on belt adapter  212 , same rotates in a defined manner such that clamp  214  supported at both ends of the axis of rotation comes into contact with the underside of lower rail  205  and locks by frictional or formfitting engagement.  
         [0029]    The fourth embodiment resembles the third embodiment. However, in the case of this supplemental locking mechanism  311 , the belt adapter  312  mounts on its longer arm in the place of the clamp, a locking comb  324 , which is made integral therewith. As a rotational lever, the belt adapter  312  is mounted to the upper rail  304  such that the locking comb  324  is able to swing downward laterally from same about the y-axis. Below locking comb  324 , a claw strip  325  with several openings is welded to lower rail  305 . When, in the event of a crash, the belt adapter  312  rotates in a defined manner because of the correspondingly great torque exerted by the belt, the locking comb  324  will engage claw strip  325 , i.e., it will lock in a formfitting engagement.  
         [0030]    The fifth embodiment is similar to the fourth embodiment. In the case of this supplemental locking mechanism  411 , the belt adapter  412  is likewise mounted to the upper rail  404  for rotation about the y-axis. An additional claw  426  extends in the interior of upper rail  404  for sliding movement in the z-direction. The additional claw  426  is provided with downward directed teeth, which are aligned with a rack bar  427  that is mounted to lower rail  405 . The longer lever arm of belt adapter  412  lies against the upward directed side of additional claw  426 , for example, against suitably shaped projections. When, in the event of a crash, the belt adapter  412  performs a defined rotation, it will push on additional claw  426 , which in turn is pushed into rack bar  427 , i.e., it will generate a formfitting engagement for locking the rails in addition.  
         [0031]    Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.