Abstract:
A safety belt apparatus for motor vehicles comprising a safety belt and a deflecting device for the safety belt which is connected to a holder which can be fastened to the vehicle via an absorption unit. The deflecting device being movable in an absorption direction by forces occurring relative to the holder with a pulling movement of the safety belt caused by an accident while overcoming an opposing absorption resistance of the absorption unit. The deflecting device being hindered from making a movement in the absorption direction with forces occurring in normal operation. The absorption unit being changeable in shape by the deflecting device moving in the absorption direction in order to overcome the absorption resistance.

Description:
BACKGROUND  
         [0001]    The invention relates to a safety belt apparatus for motor vehicles comprising a safety belt and a deflecting device for the safety belt.  
           [0002]    Such safety apparatuses are generally known. In the event of an accident, the safety belt apparatus must take up the energy of a vehicle occupant held by the safety belt. It is known for this purpose to integrate a torsion rod or bar into a reel which is deformed by a pulling movement of the belt induced by an accident when the reel is blocked. This kind of energy absorption requires a belt reel especially designed for this.  
           [0003]    It is an underlying object of the invention to provide a safety belt apparatus which ensures an optimum absorption of the energy generated by the vehicle occupant in the event of an accident with the simplest possible design and a secure and reliable functioning, and in particular without impairing the function of other components of the safety belt apparatus.  
         SUMMARY OF THE INVENTION  
         [0004]    According to the present invention, a safety belt apparatus is provided. The apparatus includes a safety belt and a deflecting device. The deflecting device being connected via an absorption unit to a holder which can be fastened to the vehicle, with the deflecting device being movable in an absorption direction by forces occurring relative to the holder with a pulling movement of the safety belt caused by an accident while overcoming an apposing absorption resistance of the absorption unit, but being hindered from making a movement in the absorption direction with forces occurring in normal operation, and with the absorption unit being changeable in shape by the deflecting device moving in the absorption direction in order to overcome the absorption resistance.  
           [0005]    In accordance with the invention, a movement of the deflecting device is used for the energy absorption. For this purpose, an absorption unit is provided between the holder fixed to the vehicle and the deflecting device cooperating with the safety belt which is formed such that it prevents a movement of the deflecting device in normal operation, while allowing a movement of the deflecting device in the absorption direction with forces such as occur in an accident and which act on the deflecting device via the safety belt. The absorption unit in accordance with the invention allows the kinetic energy of the vehicle occupant in the event of an accident to be absorbed by a change in shape of the absorption unit during the movement of the deflecting device. This change in shape can generally take place in any manner, for example by material deformation, material removal, material destruction or another kind of material processing. Combinations of different material processing kinds are also possible in accordance with the invention.  
           [0006]    The absorption device is preferably directed vertically downwardly. The deflecting device can move parallel to the vehicle side panel and parallel to a belt section extending between a belt reel and the deflecting device during the absorption of energy. It is furthermore preferably provided that the change in shape of the absorption unit is irreversible. Furthermore, the absorption unit can be deformable at least sectionally, in particular plastically, for the change in shape. In accordance with a further preferred embodiment of the invention, it is provided that the absorption unit comprises at least a part of the holder.  
           [0007]    It is proposed in a practical embodiment of the invention that the absorption unit comprises at least one bending element, in particular a strip-like or rod-like bending element, which preferably extends approximately parallel to the absorption direction between the deflecting device and the holder.  
           [0008]    The upper end of the bending element can be fastened to the deflecting device and the lower end to the holder so that the upper end is moved in the direction of the lower end by the movement of the deflecting device and deformation work is carried out at the bending element in this way. It is preferred if two bending elements are provided which extend parallel to one another and which are arranged at opposite sides of the safety belt.  
           [0009]    An alternative or additional possibility for the energy absorption consists, in accordance with a further embodiment of the invention, of a connection between at least two part sections of the absorption unit which is present during normal operation being separable for the change in shape of the absorption unit. One of the part sections may be formed by a base part which can be a component of the holder.  
           [0010]    The separation of the connection, which prevents a movement of the deflecting device in the absorption direction in normal operation, can be made in accordance with a further embodiment of the invention by an absorption section of the absorption unit being able to be torn off or out of a base part or the holder.  
           [0011]    It is furthermore possible in accordance with the invention for an absorption section of the absorption unit to be simultaneously deformable and separable from a base part or the holder.  
           [0012]    A further embodiment of the invention proposes that the change in shape of the absorption unit is effected by material removal. The material removal can take place, for example, by chip forming machining.  
           [0013]    A preferred embodiment of the invention consists of the absorption unit comprising at least one recess which can be expanded for the change in shape of the absorption unit. The recess can be formed in a slit-like manner and extend parallel to the absorption direction. In accordance with the invention, the expansion of the recess can be carried out in that material bounding the recess is deformed and/or removed. An engaging section of the deflecting device or a carrier of the deflecting device serving to hold a deflection roller can engage into the recess, with said engaging section consisting of a material whose hardness is greater than that of the material bounding the recess.  
           [0014]    The preferred material for the (s) of the absorption unit changeable in shape is steel.  
           [0015]    The deflecting device is preferably guided at the holder, in particular parallel to the absorption direction. A defined movement of the deflecting unit is ensured in this manner despite the forces to be overcome.  
           [0016]    Moreover, in accordance with a preferred embodiment, it is provided that the deflecting device comprises at least one deflection roller. The deflection roller can be supported at a carrier cooperating with the absorption unit.  
           [0017]    A preferred embodiment of the invention further proposes providing a deflecting means which cooperates with the safety belt between the deflecting device and a vehicle occupant such that the safety belt extends at least approximately parallel to the absorption direction between the deflecting device and the deflecting means. The deflecting means hereby provides an optimal guiding of the forces occurring in the event of an accident into the deflecting unit via the safety belt.  
           [0018]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    These and other features, aspects and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below.  
         [0020]    [0020]FIG. 1 a  is a front plan view of a safety belt apparatus according to the present invention;  
         [0021]    [0021]FIG. 1 b  is a schematic view of the safety belt apparatus of FIG. 1 a  as seen from the front right side;  
         [0022]    [0022]FIG. 1 c  is a schematic view of the safety belt apparatus of FIG. 1 a  as seen from the top and front of the apparatus;  
         [0023]    [0023]FIG. 2 is a perspective view of a safety belt apparatus of a further embodiment of the invention;  
         [0024]    [0024]FIG. 3 a  is a schematic view of a safety belt apparatus according to another embodiment of the present invention as seen from the back right side;  
         [0025]    [0025]FIG. 3 b  is a schematic view from the perspective of FIG. 3 a  after movement of the deflecting device in the absorption direction.  
         [0026]    [0026]FIG. 4 a  is a front plan view in partial cross section of a safety belt apparatus according to another embodiment of the present invention.  
         [0027]    [0027]FIG. 4 b  is a view from the perspective of FIG. 4 a  after movement of the deflecting device in the absorption direction. 
     
    
     DETAILED DESCRIPTION  
       [0028]    The safety belt apparatus shown in FIGS. 1 a - 1   c  comprises a holder  16  which has a holding section in the upper region for a deflecting device  14 . The apparatus may include a belt tensioner fastened to an end of the seat belt. The pretension and associated belt reel are preferably located immediately adjacent to lower end of the apparatus shown in FIGS. 1 a - 1   c.  The continuation of a safety belt  12  is schematically indicated in FIGS. 1 a - 1   c  and in the other figures by broken lines (section directed to the occupant) or by chain-dotted lines (section directed to a belt reel and pretensioner).  
         [0029]    The holder  16  may be fastened to the vehicle  42  or to the vehicle side panel  42 , which is only indicated in the figures, in particular in the region of the B or C pillar. It can be seen in particular from FIG. 1 c  that the holder  16  is preferably connected to a profile section of U-shaped cross-section of the vehicle  41 . The holder  16  and deflecting device  14  may serve as an anchor for a shoulder belt, during normal operation.  
         [0030]    The deflecting device  14  includes a deflection roller  30  which is pivotably supported in a carrier  32 . The safety belt  12  extends upwardly parallel to the holder  16  from a lower belt reel (not shown), is deflected approximately 180° by the deflection roller  30 . The belt  12  then extends downwardly approximately parallel to the holder  16  to a deflecting means  34  arranged above the belt tensioner in the shown normal operation state. The belt  12  is then guided to the respective vehicle occupant during vehicle operation. The deflecting means  34 , which is preferably fixed to the holder  16  in a vertically adjustable manner, ensures that the two belt sections  12   a  and  12   b , shown in FIG. 1 b,  extend approximately parallel to one another above the deflecting means  34 . As shown in FIGS. 1 a - 1   c,  the deflecting means  34  preferably comprises a shroud or collar surrounding both belt sections  12   a,    12   b.    
         [0031]    Two laterally arranged, strip-like bendable elements  20  extend between the carrier  32  of the deflecting device  14  and a lower region of the holder  16  disposed approximately at the height of the belt tensioner. The bending elements  20  each serve as an absorption section  26  of an absorption unit  18  jointly formed by them. The deflecting device  14  or the carrier  32  is connected to the holder  16  via the absorption unit  18 . No additional connection, which could counter a vertical movement of the carrier  32  relative to the holder  16  with a relevant resistance, is present between the deflecting device  14  and the holder  16 .  
         [0032]    The carrier  32  cooperates with the holder  16  to the extent that a vertical movement of the carrier  32  is guided through the holder  16 . For this purpose, the carrier  32  has a guide section of which two arms  32   a  extending perpendicular to the axis of rotation of the deflection roller  30  are shown in FIGS. 1 a  to  1   c.  The arms  32   a  of the guide section grip around a vertical guide rail  16   a  of the holder  16 . The absorption sections  26  are each connected to the arms  32   a  of the carrier  32  via their upper, U-shaped, inwardly bent ends.  
         [0033]    Moreover, the deflecting means  34  is attached to the guide rail  16   a  of the holder  16 , as can be seen in particular from FIG. 1 c.    
         [0034]    The lower end of each of the bending strips  20  is bent inwardly in a hook-like manner so that the bending strips  20  extend in offset parallel manner to the guide rail  16   a . The bending elements  20  are preferably made of metal, in particular of steel.  
         [0035]    The strength or flexural strength of the bending strips  20  is selected so that forces acting on the deflecting device  14  via the belt  12  in normal operation cannot bend the strips  20  or can at best bend them only to a negligible degree. The deflecting device  14  is therefore not forced to move downward in normal operation. The absorption unit  18  formed by the strips  20  thus ensures a normal operation of the deflecting device  14 .  
         [0036]    The absorption unit  18  is designed so that in the event of an accident when the respective vehicle occupant abruptly pulls on the belt  12  due to his momentum and causes the belt reel to lock, the forces which thereby act on the deflecting device  14  via the belt  12  and which are essentially directed vertically downwardly are sufficient to deform the bending elements  20 . In the event of an accident, the deflecting device  14  is consequently moved vertically downwardly along the guide rail  16   a  of the holder  16  while deforming the bending elements  20 . The kinetic energy of the vehicle occupant is thus absorbed by the deforming of the bending elements  20 . Work is performed at the absorption unit  18  which results in a change in shape of the absorption unit  18  in order to absorb the motion energy of the vehicle occupant in this way.  
         [0037]    By a corresponding design of the bending elements  20 , it is thus generally possible to absorb energies of any size in a very short path, i.e. by a comparatively short vertical path of the deflecting device  14 . The design and function of neither the belt reel nor other components of the safety belt apparatus are impaired by the type of energy absorption provided by the present invention.  
         [0038]    Further examples for the energy absorption in accordance with the invention, in which shape changing work is performed at an absorption unit in order to absorb energy, are described below.  
         [0039]    [0039]FIG. 2 shows an alternative embodiment of the present invention in which the absorption unit  18  comprises, in addition to bending strips  20  serving as absorption sections  26 , two further strip-like elements which are also termed base parts  24  in the following description.  
         [0040]    The safety belt apparatus is shown during or at the end of the energy absorption in FIG. 2. The deflecting device  14  is located below its normal position which it assumes during normal operation.  
         [0041]    The bending strips  20  and the base strips  24  are fixedly connected to one another along a linear desired separation point  22  during normal operation. The two strips  20 ,  24  can, for example, be welded together to form the connection. It is also possible to provide a deliberate material weakness in a one-piece starting strip, for example by forming a groove or a notch, in order to manufacture the desired separation point  22 .  
         [0042]    When the deflecting device  14  is moved downwardly in the event of an accident due to the forces applied via the safety belt  12 , then not only a deformation of the bending strips  20  takes place, but energy must also be used in order to separate the connection between the two strips  20 ,  24  at the desired separation point  22 .  
         [0043]    Consequently, a combined energy absorption takes place in the absorption unit  18  formed by the two double strips  20 ,  24 , with which the behavior of the absorption unit  18  can be deliberately set in a particularly advantageous manner.  
         [0044]    [0044]FIGS. 3 a  and  3   b  show yet another alternative embodiment of the present invention in which, in turn, a deformation of an absorption section  26  formed as a strip-like bending element  20  and the separation of a connection between the bending strip  20  and a plate-like base part  24 , which is solid during the normal operation in accordance with FIG. 3 a , takes place simultaneously.  
         [0045]    In the embodiment shown, the plate-like base part  24  is a component of the holder  16 . It is also possible to provide a part of the vehicle or the vehicle side panel itself as a base part from which the absorption section  26  can be separated for energy absorption and at which a holder for the safety belt apparatus is fastened.  
         [0046]    During normal operation, the bending strip  20  is integrated into the base part  24  such that the two parts jointly form a continuous plate. As FIG. 3 b  shows, when the deflecting device  14  is moved vertically downwardly, in order to absorb energy, the bending strip  20  is, on the one hand, deformed and, on the other hand, pulled or torn off the base part  24  at least in part along the linear desired separation points  22 , in similar manner to the lid of a can of sardines.  
         [0047]    The separation in accordance with the invention of a fixed connection, which prevents a movement of the deflecting device  14  in the absorption direction, i.e. vertically downwardly in the embodiments shown, with forces occurring in normal operation and which is present between an absorption section  26  and a base part  24  of the absorption unit  18 , can be designed such that the absorption section  26  is torn off or out of the base part  24 .  
         [0048]    A further embodiment of the present invention is shown in FIGS. 4 a  and  4   b.    
         [0049]    The only partly shown safety belt apparatus comprises a holder  16  with a guide rail  16   a  extending in the vertical direction. The carrier  32  of the deflecting device  14  supports a deflection roller  30  and cooperates with the guide rail  16   a  in that two engaging sections  48  of the carrier  32  each engage into a slit-like recess  28  formed in the guide rail  16   a.    
         [0050]    In the normal operating state in accordance with FIG. 4 a , the engaging sections  48  are seated in the starting regions of the recesses  28 , which are dimensioned in accordance with the outer shape of the engaging sections  48  and thus have a width sufficient for the engaging sections  48 . Regions  29  of the slits  28  adjacent hereto are, however, narrower than the engaging sections  48  so that the engaging sections  48  are larger than these slit regions  29  located in front of the engaging sections  48  in the absorption direction.  
         [0051]    The absorption unit  18  is formed in this embodiment by the slits  28  and the guide rails  16   a  or by the material of the guide rail  16   a  bounding the slits  28 .  
         [0052]    When, in the event of an accident, the deflecting device  14  is pulled downwardly via the safety belt (not shown), the change in shape of the absorption unit  18  takes place by material removal at the guide rail  16   a . The engaging sections  48  are able to cut the slits  28  by material removal along their own width by an appropriate choice of the material for the carrier  32  or at least its engaging sections  48 , on the one hand, and for the guide rail  16   a  or at least its regions bounding the slits  28 .  
         [0053]    The energy absorption thus takes place by chip forming machining at the guide rail  16   a . The removed material  46  is shown in FIG. 4 b . Thus, as the engaging sections  48  move downwardly through the slits  28  they remove material from the surrounding portions of the guide rail  16   a  due to the size difference between the engaging sections  48  and the slots  28 .  
         [0054]    The absorption properties of the absorption unit  18  can be deliberately set in particular by the number of engaging sections  48  and recesses  28 , the size ratios between the engaging sections  48  and the recesses  28  and/or the choice of material for the engaging sections  48  and the regions of the guide rail  16   a  bounding the recesses  28 .  
         [0055]    The carrier  32  is simultaneously guided at the guide rail  16   a  and thus at the holder  16  during the energy absorption by the carrier sections  48  engaging into the recesses  28 . This cooperation between the carrier  32  and the guide rail  16   a  can be designed in an advantageous manner such that no additional measures are required for the guiding of the deflecting device  14  at the holder  16 .  
         [0056]    In accordance with the invention, the deflecting device could also be directly connected to the vehicle or the vehicle side panel via the absorption unit. The holder within the meaning of the invention is then formed by the means, e.g. in the form of screw connections or weld points, with which the absorption unit is fastened to the vehicle.  
         [0057]    The priority document, DE 10103319.2 filed Jan. 25, 2001, is incorporated by reference herein in its entirety.