Abstract:
The invention relates to a seat belt ( 2 ) for motor vehicles, having a restraining element ( 4 ) for a seat belt tongue ( 3 ). The restraining element protrudes from the seat belt ( 2 ), from only on one side thereof and the seat belt ( 2 ) may be configured as a multi-layer seat belt ( 2 ) forming a hollow space ( 5 ) between the seat belt layers ( 21, 22 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to DE 10 2005 058 343.1, filed Dec. 6, 2005 and PCT/EP2006/011001, filed Nov. 16, 2006. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a seat belt for motor vehicles, comprising a restraining element for a seat belt tongue slidable along seat belt webbing, the element protruding from one side surface of the seatbelt. 
       BACKGROUND OF THE INVENTION 
       [0003]    From the state of the art seat belts are known, wherein a restraining element, a so-called a strap button, is provided in order to hold a seat belt tongue in a predefined position in a parking position of a belt system (while the belt is not fastened). This strap button is made of two or more parts which are pierced or pushed on both sides through the belt webbing of the seat belt and are held together by means of a clip or pin connection. The strap button prevents the seat belt tongue from resting on the seat cushion in the inoperative position and allows the seat belt tongue to be positioned in the desired position to be conveniently accessed by a user. A strap button of this type is known from US 2004/0250387 A1. 
         [0004]    The strap button protruding from the seat belt on both side surfaces of belt webbing in accordance with the prior art creates an aesthetic impairment and makes it necessary to configure the seat belt tongue on the side facing away from the seat cushion such that the seat belt tongue can be suspended in a flat manner in the inoperative position and rest against the seat belt. 
         [0005]    Penetration of the seat belt webbing entirely through its thickness when the strap button elements are joined results in weakening of the webbing material. In addition, if inflatable seat belts are used, it is difficult to guarantee sufficient gas flow in the region of the strap button since the prior art connection approach prevents the webbing from being easily inflated and provides clearance for the flow of gas through its interior. 
         [0006]    DE 103 27 753 A1 describes a sensor arrangement to be attached to a belt, particularly to a seat belt of a motor vehicle, wherein a sensor is attached to the belt on the upper side of the belt facing away from the passenger. The sensors determine the heart rate, for example, or the body temperature, or they can be configured as microphones. 
         [0007]    It is the object of the present invention to provide a seat belt which is comfortable to use, provides occupant safety, and is visually appealing. 
         [0008]    This object of the invention is achieved according to the invention by a seat belt having the characteristics described herein. Advantageous embodiments and further developments of invention are also disclosed. 
         [0009]    The seat belt for motor vehicles according to the invention, includes a restraining element for a seat belt tongue, the element protruding from the seat belt, provides for a one-sided arrangement of the restraining element on the seat belt such that one side of the seat belt, preferably the side facing the user of the belt, has no projecting or protruding restraining element or a belt buckle latch stopper. In the parking position, the buckle latch rests flat against the seat belt since the restraining element visibly and effectively projects only on the seat belt back surface. In this way, in the parking position, protrusion of the belt front surface in the direction of the vehicle interior is eliminated. The invention further provides that the seat belt may be configured as a multi-layer seat belt comprising a hollow space, wherein the belt can be filled with an appropriate gas via a gas generator. This hollow space is formed by a plurality of seat belt layers and is used for inflatable seat belt systems. 
         [0010]    In order to be able to also use seat belt tongues that have a wider belt slot, it is provided that the restraining element of this invention is at least 4 mm thick in order to be able to guarantee secure fastening of the seat belt tongue in the desired position. 
         [0011]    Likewise, it is possible that the restraining element extends at least across half the width of the seat belt, preferably across nearly the entire width of the belt webbing, in order to cover corresponding slot cross-sections and thus guarantee secure association of the seat belt tongue with the seat belt. On the correspondingly large restraining elements, a label with informational content may be applied, which provides information, for example, about the design features or the properties of the seat belt, or warnings required by regulations. In this case, the restraining element is preferably disposed on the visible side surface of the belt webbing such that the informational content of the label can be identified by the belt user. Furthermore, arranging the restraining element on the visible side surface has the advantage that, particularly in the case of belt systems integrated in the seat, the restraining element does not negatively influence the storage position, thus producing an orderly appearance overall. 
         [0012]    It is provided that the restraining element is fastened in the conventional manner to the seat belt layer, which is to say it is positively fastened by a mechanical fastener to the inside of the seat belt to a layer of the seat belt in order to fix the seat belt tongue in place. A basic alternative to the positive mechanical attachment is to glue or weld it on as a non-positive or bonded connection of the restraining element to one side of the seat belt or one side surface of a seat belt layer. 
         [0013]    In all cases this ensures that the inflation behavior of an inflatable seat belt is not changed and that using comfort is not impaired by the fact that part of the restraining element is disposed on the side surface facing the belt user in the operating or usage position. To this end, the restraining element is preferably disposed on the side surface of the seat belt fading the backrest cushion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The invention will be explained in more detail hereinafter with reference to the attached figures, wherein: 
           [0015]      FIG. 1  is a schematic, perspective illustration of a belt system; 
           [0016]      FIG. 2  is a cross-sectional view of  FIG. 1 ; 
           [0017]      FIG. 3  is a cross-sectional view of a further embodiment; and 
           [0018]      FIG. 4  is a variant of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]      FIG. 1  shows a belt system  1  comprising a seat belt  2  and a seat belt tongue  3 . The seat belt tongue  3  threaded into in a belt buckle and positively locked when the seat belt  2  is attached. The seat belt tongue  3  is attached displaceably on the seat belt  2 .  FIG. 1  shows the seat belt  2  in the inoperative position (i.e. the belt system is not fastened around the user), in which it is guided substantially vertically from an upper belt deflection point to a lower anchorage. In this position, the seat belt tongue  3  rests on the restraining element  4 , which extends substantially across the entire width of the seat belt  2 , wherein the restraining element  4 , on the surface of which lettering  7  or another symbol may be provided, is located on the back surface of the seat belt  2 , which is to say on the side surface facing away from the belt user. The seat belt tongue  3 , on the other hand, protrudes with the seat belt tongue end that can be inserted in the belt buckle in the direction of the belt user such that the user can easily grasp the seat belt tongue  3 . The restraining element  4  prevents the seat belt tongue  3  from sliding down to the seat belt anchorage and holds the seat belt tongue  3  at grip height for the belt user. 
         [0020]      FIG. 2  shows the embodiment of the seat belt from  FIG. 1  in a cross-sectional view. In the example of the invention shown in  FIG. 2  the seat belt  2  is made of two belt layers  21 ,  22 , between which a hollow space  5  is formed, through which gas from a gas generator can be introduced into the seat belt  2 . In the event of an accident, the seat belt  2  inflates and provides improved restraining action. In order to enable gas passage through the seat belt tongue  3  without difficulty, a relatively wide belt slot is configured within the seat belt tongue  3 . Accordingly, the restraining element  4  is slightly thicker than the width of the belt slot. 
         [0021]    It is apparent from  FIG. 2  that the restraining element  4  is disposed only on the outside of a seat belt layer  22 . The seat belt webbing is not penetrated, rather an adhesive region  6  is provided between the restraining element  4  and the seat belt layer  22 . Alternatively, the restraining element  4  can also be welded to the seat belt  2  or welded to the seat belt layer  22 . Likewise, in the case of a two-layer configuration of the seat belt  2 , it is possible to penetrate one layer  21 ,  22  and fix the restraining element  4  to the one layer  22  in a conventional manner. A corresponding counter-piece for the restraining element  4  is then accommodated on the inside in the hollow space  5 . 
         [0022]      FIG. 3  shows a cross-sectional view of an alternative embodiment, wherein the restraining element  4  is positively fastened through a mechanical fastening connection to a layer  22  of the seat belt  2 . Positively locking elements  41 , which are fastened to or configured on the restraining element  4 , penetrate the top layer  22  of the seat belt  2  and engage a counter-piece  14  there. The counter-piece  14  is introduced in the hollow space  5  formed by the two seat belt layers  21 ,  22  and/or is fastened to the top layer  22 , while the bottom layer  21  is fixed to the top layer  22 , for example is glued or welded thereto. The counter-piece  14  comprises tapered inserts  16 , by means of which the arrow-shaped positively locking elements  41  can be introduced into corresponding recesses  15  where they engage and lock together. Laterally, adjacent to the recesses  15  and/or the tapered inserts  16 , relief recesses  17  are provided, which enable springback of the sides of the recess  15  that are provided with an undercut which facilitates snap-fit attachment of locking elements  41  into recesses  15 . 
         [0023]    Between the two layers  21 ,  22  of the seat belt, a seal  23  or an intermediate layer may be disposed. 
         [0024]    Alternatively to the illustrated, solely two-ply configuration of the seat belt  2 , it is possible to provide an expanding inflatable body made of an elastic, preferably gastight material, within the free space  5  formed between the top layer  22  and the bottom layer  21 , wherein the gas of the gas generator is introduced into the expanding body. The two layers  21 ,  22  then serve as a casing for the expanding body, which preferably has a tube-shaped and single-piece configuration, in order to avoid or minimize leaks. In this way, gas is prevented from escaping from the hollow space  5  through the holes of the positively locking elements  41  within the seat belt layer  22 . Likewise, fabric that feels comfortable and has sufficiently high tensile strength can be used for the seat belt layers  21 ,  22 , without having to ensure increased gas tightness at the same time as protection against accidental leakage of the gas through the seat belt in the direction of the belt user. 
         [0025]    Such a variant of the seat belt is shown in  FIG. 4 , wherein the two seat belt layers  21 ,  22  are shown unconnected to one another. The expanding body  24  is disposed within the free space  5  between the seat belt layers  21 ,  22  and is in a flat, compressed state beneath the counter-piece  14  and between the counter-piece  14  and the bottom seat belt layer  21 . On the seat belt layer  21 ,  22  outer ends, which are not shown, a weld connection, glued connection, or sewn connection can be provided, and optionally the seat belt can also be configured as one piece and receive both the counter-element  14  and the expanding body  24 , which is connected to the gas generator by a fluidic connection. 
         [0026]    In the applied position (i.e. when the seat belt  2  is worn by the user), the restraining element  4  is located on the top surface of the seat belt  2 , that is on the side of the lap belt facing away from the belt user, and does not impair the usage and sliding behavior. The provided adhesive technique simplifies the assembly process and furthermore does not weaken the fabric of the seat belt  2 . As a result of the one-sided application and/or one-sided attachment of restraining element  4 , it is possible not to impair the function of the seat belt  2 , particularly also when configured as an inflatable seat belt. In the case of a double-layered configuration, the restraining element  4  can also be press-fitted with a fabric layer. 
         [0027]    While the above description constitutes the preferred embodiment of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.