Abstract:
A plug-in tongue for a belt buckle of a seatbelt system. The tongue includes a plug-in section suitable for plugging into the belt buckle and with a belt-retaining section which has a slot for the passage and deflection of a seat belt. The plug-in tongue includes a metal plate which has a slot-shaped opening, and wherein at least one edge section of the metal plate, which edge section bounds the slot-shaped opening, is embedded into a plastics material. The edge section of the metal plate, which edge section bounds the slot-shaped opening, is bent out of the opening plane of the slot-shaped opening and has a hook-shaped cross section.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
       [0001]    This application is a continuation of International Patent Application Number PCT/DE2012/200070, filed Nov. 7, 2012, which was published in German as WO 2013/071927. The foregoing international application is incorporated by reference herein. 
       BACKGROUND 
       [0002]    This application relates to an insertion tongue for a belt lock of a safety belt system. 
         [0003]    Such an insertion tongue is known, for example, from the German Offenlegungsschrift DE 10 2007 043 338 A1. This insertion tongue has an insertion portion which is suitable for insertion in a belt lock of a safety belt system. Furthermore, the insertion tongue is provided with a belt retention portion which has a slot for introducing and redirecting a safety belt. The insertion tongue comprises a metal plate which has a slot-like opening. The position of the slot-like opening correlates to the slot of the insertion tongue, through which slot the safety belt can be guided for redirection. The edge of the metal plate delimiting the slot-like opening is embedded in a plastics material. 
       SUMMARY OF THE INVENTION 
       [0004]    An object of the invention is to provide an insertion tongue which can be produced in a simple and cost-effective manner and which has a high level of mechanical stability. 
         [0005]    Accordingly, there is provision for an insertion tongue to include an edge portion of a metal plate, which portion delimits a slot-like opening, to be bent out of an opening plane of the slot-like opening and to have a hook-like cross-section. 
         [0006]    A significant advantage of the insertion tongue can be seen in that it is possible to produce therein a plastics coating which is at least approximately circular in cross-section in a very simple manner in the region of the slot-like opening. The plastics material can be applied in the region of the bent-over edge portion—as a result of the hook-like cross-section—with at least substantially the same thickness or wall thickness, whereby the production of the plastics coating is significantly improved, in particular in the case of the metal plate being covered with plastics material via injection molding. There is also less material waste and fewer sink marks, shrink holes or cracks are formed. 
         [0007]    Another significant advantage of the insertion tongue is that the stability of the insertion tongue is very great. If the safety belt, for example, in the case of an accident, applies a pulling force to the insertion tongue, the plastics material is supported by the bent hook-like edge portion over a large surface-area. The tensile loading is consequently received both by the plastics material and by the edge portion which retains or supports the plastics material. As a result of the hook-like cross-section in the region of the edge portion of the metal plate, therefore, there are no corners or edges which could act on the plastics material in a wedge-like manner in the event of tensile loading and potentially destroy it. As a result of the shaping of the edge portion, deformations which can lead to an overload of the plastics material—brought about by the different levels of resilience of metal and plastics material—occur only in the case of very high forces and consequently significantly later than would be the case with conventional shaping of the metal plate. 
         [0008]    A third significant advantage of the insertion tongue is that, in spite of the significant mechanical advantages mentioned, it can nonetheless be produced in a simple and cost-effective manner since the shaping of the bent edge portion of the metal plate can be achieved, for example, simply by means of punching, deep-drawing and bending of a metal sheet. 
         [0009]    A fourth significant advantage of the insertion tongue is that, as a result of the shaping, that is to say, the hook-like cross-section, significant strengthening of the metal plate is achieved whereby, in the case of a high mechanical loading, for example, in the event of an accident, the danger of breaking or bending of the insertion tongue is significantly reduced. As a result of the high level of stability of the bent metal plate, it is further possible to use relatively thin metal sheets for the production thereof so that the production is more simple and cost-effective. 
         [0010]    The bent edge portion is preferably the edge of the two opposing long edges of the slot-like opening that has the greater spacing from the insertion portion. 
         [0011]    With regard to particularly great stability of the bent edge portion, it is considered to be advantageous for the edge portion to be bent through an angle of between 90° and 180°, in a particularly preferred manner through an angle between 90° and 135°. 
         [0012]    The bent edge portion preferably has a deep-drawn portion which is adjoined by a bent portion. The hook-like cross-section of the bent edge portion thus preferably comprises two production steps, that is to say, a deep-drawing step, in which inter alia the deep-drawn portion is formed, and a bending step, in which the bent portion is formed. 
         [0013]    The width of the hook opening of the bent edge portion, that is to say, the spacing between the front hook tip and the location of the edge portion opposite the hook tip is preferably at least as large as the thickness of the metal plate itself. Such a width of the hook opening makes it easier to embed the belt retention portion in the plastics material, in particular when the belt retention portion is coated with plastics material via injection molding. 
         [0014]    The bent edge portion of the metal plate may, for example, have a cross-section which corresponds in terms of shape to the upper portion of a question mark. 
         [0015]    It is considered to be particularly advantageous for the plastics material to form in the region of the bent edge portion a plastics layer which is at least partially curved, preferably in the form of a circular arc, in cross-section. 
         [0016]    With regard to simple production, for example, in the case of coating with plastics material via injection molding, and with regard to maximum stability of the insertion tongue, it is considered to be advantageous for the outer side of the bent edge portion, which outer side faces the slot or the slot-like opening, to be partially curved, preferably curved in the form of a circular arc, in cross-section and for the curved outer side to be provided with a plastics layer which is curved in cross-section, preferably in the form of a circular arc. The layer thickness of the curved plastics layer which is preferably curved in the form of a circular arc is preferably between 0.7 and 3 mm. 
         [0017]    The variation of the layer thickness is preferably less than 10% of the mean layer thickness of the curved plastics layer. 
         [0018]    In order to prevent the safety belt from being able to slide through the slot of the insertion tongue in an unimpeded manner in the event of a vehicle accident or in the event of great tensile loading, it is considered to be advantageous for there to be formed, at the outer side on the plastics layer which is curved in cross-section, plastics material teeth which extend away from the bent edge portion of the metal plate. 
         [0019]    In a particularly preferred manner, the teeth have a cross-section which inhibits sliding of the safety belt in one direction more than in the other direction. The cross-section of the teeth is preferably fin-like. 
         [0020]    The tip of the teeth is preferably orientated in such a manner that, when the safety belt is positioned, the teeth inhibit the safety belt from sliding along from the shoulder region in the direction of the pelvic region. 
         [0021]    In order to achieve optimum stability of the teeth, it is considered to be advantageous for the height of the teeth to be a maximum of 1.5 times the thickness of the curved plastics layer. 
         [0022]    With regard to the orientation of the teeth relative to the orientation of the hook tip of the bent edge portion, it is considered to be advantageous for the tip of the teeth to be bent away in the same rotation direction as the hook tip of the bent edge portion. Alternatively, the tip of the teeth may be bent counter to the rotation direction of the hook tip of the bent edge portion. 
         [0023]    In order to achieve an optimum angle between the insertion tongue and the safety belt, when the insertion tongue is freely suspended on the safety belt, it is considered to be advantageous for the belt retention portion to be bent out of the plane of the insertion portion and for the extent direction of the slot to have an angle with respect to the insertion portion between 10 and 19 degrees. The term “extent direction of the slot” is in this instance intended to be understood to be the direction in which the safety belt extends relative to the insertion tongue when the tongue is freely suspended on the safety belt which extends perpendicularly and which is retained in a tensioned state. The influence of a belt strap stopper on the resulting angle can be compensated for by means of a recess in the insertion tongue. 
         [0024]    With regard to optimum stability of the insertion tongue and simple production, it is considered to be advantageous for the bent edge portion of the metal plate to be bent, in particular bent at right angles, out of the opening plane of the slot-like opening in the direction toward the plane of the insertion portion. 
         [0025]    Alternatively, there may be provision for the bent edge portion of the metal plate to be bent, in particular bent at right angles, out of the opening plane of the slot-like opening, away from the plane of the insertion portion. 
         [0026]    The bent edge portion of the metal plate is preferably embedded in a plastics strand, which has an outer contour which is partially curved in cross-section and which is in particular curved in the manner of a circular arc. The curved outer contour of the plastics strand is preferably orientated parallel or partially concentrically relative to the outer contour of the bent edge portion. 
         [0027]    The curved outer contour of the plastics strand is preferably provided at least partially with teeth and partially with webs which have a smooth outer face. The function of the webs or the smooth outer face thereof is to make it easier to slide the safety belt over the plastics strand in the event of no or only a small tensile loading of the safety belt. However, if the tensile force of the safety belt is increased, the safety belt will come into contact with the teeth at the outer contour of the plastics strand and, depending on the sliding direction, be prevented from sliding to a greater or lesser extent by the teeth. 
         [0028]    The webs are preferably guided radially around the outer contour of the plastics strand. In this instance, there may be provision for the webs to extend in an oblique manner around the outer contour of the plastics strand. 
         [0029]    It is further considered to be advantageous for the insertion tongue to have an end portion which is separated from the insertion portion by the belt retention portion. The end portion and the insertion portion are preferably arranged parallel with each other. 
         [0030]    As disclosed herein, an insertion tongue for a belt lock of a safety belt system is provided. The insertion tongue includes an insertion portion which is suitable for insertion in the belt lock and a belt retention portion which has a slot for introducing and redirecting a safety belt, the insertion tongue further comprising a metal plate having a slot-like opening. 
         [0031]    There is provision for an edge portion of the metal plate, which edge portion delimits the slot-like opening, to be embedded in a plastics strand which has a partially curved outer contour in cross-section and for the outer contour of the plastics strand to be at least partially provided with teeth which inhibit sliding of the safety belt in one direction more than in the other direction. As already mentioned above, the safety belt is preferably intended to come into contact with the teeth on the outer contour of the plastics strand only in the event of a high tensile force, but not during normal operation; during normal use there should preferably not be produced any inhibition action, regardless of the direction. Inhibition should preferably occur only in critical situations, that is to say, under high loading and preferably in only one direction. 
         [0032]    With regard to the advantages of this insertion tongue, reference may be made to the above statements. 
         [0033]    The application further discloses a method for producing an insertion tongue. The method includes a provision for a metal plate to be punched, with a slot-like opening being formed, for the punched metal plate to be deep-drawn and for an edge portion of the metal plate, which edge portion delimits the slot-like opening, to be bent out of the opening plane of the slot-like opening in such a manner that the bent edge portion has a hook-like cross-section and for the bent edge portion to be embedded in a plastics material. The sequence of the deep-drawing step and the bending step can be freely selected. 
         [0034]    With regard to the advantages of the method, reference may be made to the above statements with regard to the insertion tongue since the advantages of the method according substantially correspond to those of the insertion tongue. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0035]    The invention is explained in greater detail below with reference to embodiments; by way of example in the drawings: 
           [0036]      FIGS. 1 to 8  show a first embodiment of an insertion tongue, 
           [0037]      FIGS. 9 to 15  show a second embodiment of an insertion tongue, and 
           [0038]      FIGS. 16 to 19  show a third embodiment of an insertion tongue. 
       
    
    
     DETAILED DESCRIPTION 
       [0039]    In the Figures, for the sake of clarity, the same reference numerals are always used for components which are identical or comparable. 
         [0040]      FIGS. 1 to 8  show a first embodiment of an insertion tongue  10 . The insertion tongue  10  comprises an insertion portion  11  and a belt retention portion  12  which is provided with a slot  13 . 
         [0041]    The insertion portion  11  is provided with a recess  11   a  through which a locking element of a belt lock can engage in order to retain the insertion tongue  10 . 
         [0042]    A safety belt  20  can be guided through the slot  13  in order to redirect it.  FIG. 1  shows that the extent direction R of the slot  13  forms with respect to the insertion portion  11  an angle a which is preferably in the range between 10° and 19°. 
         [0043]      FIG. 2  is a three-dimensional view of the insertion tongue  10  according to  FIG. 1 . The insertion portion  11 , the belt retention portion  12  and the slot  13  can be seen. It is further possible to see a plastics strand  30  which delimits the long edge  13   a  of the slot  13 . Opposite the long edge  13   a  is a long edge  13   b  of the slot  13 , which has a smaller spacing with respect to the insertion portion  11  than the other opposing long edge  13   a.    
         [0044]    In  FIG. 2 , it can further be seen that the plastics strand  30  is at least partially circular in cross-section. The surface of the plastics strand  30  has four webs  40  which have a smooth surface so that the safety belt can slide over it. Between the webs  40  are portions having teeth  50  whose cross-section in a radial direction is at least substantially fin-like. 
         [0045]      FIG. 3  is yet another view of the insertion tongue  10  according to  FIG. 1 . Here again, the plastics strand  30 , the webs  40  and the teeth  50  can be clearly seen. 
         [0046]    In  FIG. 4 , the insertion tongue  10  according to  FIG. 1  is illustrated as a section. It can be seen that the insertion tongue  10  has a metal plate  60  having a slot-like opening  70  whose position correlates to the position of the slot  13  of the insertion tongue  10 . 
         [0047]    The inner edge portion  80  of the metal plate  60 , which portion delimits the slot-like opening  70  in the region of the edge  13   a  of the slot  13 , has been bent out of the opening plane of the slot-like opening  70  so that a hook-like cross-section is formed. In the embodiment according to  FIG. 4 , the edge portion  80  is bent in the direction toward the plane of the insertion portion  11 , that is to say, downward in the illustration according to  FIG. 4 . 
         [0048]      FIG. 5  is a cut-away side view of the insertion tongue according to  FIG. 1 . It is possible to see the hook-like edge portion  80  which is embedded in a plastics material  90 . The shaping of the bent edge portion  80  makes it possible for the outer side  81  of the edge portion  80  facing the slot or the slot-like opening  70  to be partially circular in cross-section. The plastics material  90  consequently forms on the outer side  81  of the bent edge portion  80  a plastics layer  91  which is consequently also partially circular in cross-section. 
         [0049]    The plastics layer  91  which is circular in cross-section has a layer thickness which—without taking into account the teeth  50  formed on the plastics layer  90 —is substantially constant. The variation in layer thickness of the plastics layer  91  is preferably less than 10% of the mean thickness of the plastics layer  91  in the region of the circular outer side  81  of the hook-like edge portion  80 . 
         [0050]    In  FIG. 5 , it is further possible to see the shaping of the teeth  50  in greater detail. It can be seen that the teeth  50  have a fin-like cross-section by means of which a preferred direction is defined. As a result of the fin-like cross-section, the teeth  50  inhibit sliding of the safety belt  20  according to  FIG. 1  to differing degrees in accordance with the sliding direction. The orientation of the teeth  50  or the fin-like cross-section is preferably selected in such a manner that the teeth, when the safety belt is positioned (and in the event of high tensile force, see above) inhibit the sliding of the safety belt from the shoulder region of the vehicle occupant in the direction of the pelvic region of the vehicle occupant more than in the opposing direction. 
         [0051]    In  FIG. 5 , it can further be seen that the height of the teeth  50  is approximately as large as the thickness of the plastics layer  91 . The height of the teeth  50  is preferably in a range between 0.7 times and 1.5 times the thickness of the plastics layer  91 . With such a thickness, the stability of the teeth  50  and the force transmission by the teeth  50  to the plastics layer  91  and consequently to the bent outer side  81  of the bent edge portion  80  is optimal. 
         [0052]    Furthermore,  FIG. 5  shows that the orientation of the fin-like teeth  50  corresponds to the bending direction of the bent edge portion  80 . The bent edge portion  80  in  FIG. 5  is thus bent upwards, which in terms of orientation corresponds to the fin orientation of the teeth  50 . 
         [0053]      FIG. 6  shows the shaping of the metal plate  60  of the insertion tongue  10  in greater detail. It is possible to see the bent edge portion  80  which is bent in the direction toward the plane of the insertion portion  11 . 
         [0054]      FIGS. 7 and 8  are other views of the metal plate  60  of the insertion tongue  10  according to  FIG. 1 . It can readily be seen in particular in  FIG. 8  that the metal plate has an end portion  14  which is separated from the insertion portion  11  by means of the belt retention portion  12 . The end portion  14  of the insertion tongue  10  and the insertion portion  11  are preferably located in mutually parallel planes or at a slight angle, preferably up to a maximum of from 10° to 15°. 
         [0055]      FIGS. 9 to 15  show a metal plate  60  for a second embodiment for an insertion tongue  10 . It can be seen that, in the embodiment according to  FIGS. 9 to 15 , the upper edge portion  80  of the metal plate  60  is bent or bent at right angles away from the plane of the insertion portion  11 . The bending direction of the upper edge portion  80  is thus the reverse of the bending direction as provided for in the embodiment according to  FIGS. 1 to 8 . 
         [0056]    In particular in  FIGS. 10 and 13 , the shaping of the upper edge portion  80  can be seen particularly clearly. It can thus be seen that the bent edge portion  80  has a deep-drawn portion  82  (cf.  FIG. 11 ) which is adjoined by a bent portion  83 . Therefore, the hook-like cross-section of the bent edge portion  80  is consequently formed by two production steps, that is to say, a deep-drawing step in which the deep-drawn portion  82  is formed, and a bending step, in which the bent portion  83  is formed. 
         [0057]    The metal plate  60  according to  FIGS. 9 to 15  can in further production steps be embedded in plastics material, as has already been explained with reference to  FIGS. 1 to 8 . In this instance, it is possible to form a plastics strand which is provided with webs and teeth and which embeds the upper edge portion  80  of the metal plate  60 . In this regard, reference may be made to the above statements. 
         [0058]      FIGS. 16 to 19  show a third embodiment for an insertion tongue  10 , but in which the edge portion  80  is not bent in a hook-like manner.  FIG. 16  is a three-dimensional illustration of the insertion tongue  10  in the cut-away state. It can be seen that the edge portion  80  of the metal plate  60  is embedded in a plastics strand  30  whose outer side has webs  40  (sliding webs) and teeth  50 . The orientation of the webs  40  is different to that in the first embodiment according to  FIGS. 1 to 8 . It can thus be seen that the webs  40  are also guided radially, but in a slightly oblique manner around the outer side of the plastics strand  30 . 
         [0059]      FIGS. 17 ,  18  and  19  show the structure of the teeth  50  in greater detail. It can be seen that the teeth are fin-like in cross-section and thereby bring about a different inhibiting action in the event of the safety belt sliding past. 
         [0060]    If, for example, in the illustration according to  FIG. 19 , the safety belt is pulled in the arrow direction P 1  through the slot  13 , the inhibiting action of the teeth  50  as a result of the fin shape will be very small. However, if the safety belt is pulled downward in the arrow direction P 2  in  FIG. 19 , the fin-like teeth  50  will prevent the safety belt from sliding past in the event of significant tensile force, at least inhibit it significantly more than in the other direction. In order to ensure this operation, it is considered to be advantageous for the height difference between the height of the tooth tips and the height of the webs  40  (sliding webs) to be approximately from 0 to 0.6 mm. 
         [0061]    The slot spacing which defines the spacing between the webs (sliding webs)  40  and the lower opposing edge of the area coated via injection molding preferably has such dimensions that free movement of the belt strap during normal use is ensured in both directions. The slot spacing preferably further has such dimensions that unintentional rotation of the belt strap in the slot is not possible either during normal use or during a critical situation. 
         [0062]    The two outer sliding webs are preferably wider than the inner sliding webs. The two outer sliding webs are preferably so wide that, even in the event of oblique or other belt strap guiding, sliding is still ensured during normal use. 
         [0063]    The position of the inner sliding webs is preferably selected in such a manner that, for example, in an asymmetrical manner, even in the event of curvature of the belt strap during normal use (for example, also during fastening or unfastening), there is no inhibition action. 
         [0064]    The mechanical stability of the teeth is preferably sized by means of material selection and/or geometry in such a manner that the teeth fail before the belt strap fails. 
         [0065]    The priority application, German Patent Application No. 10 2011 086 373.7, filed Nov. 15, 2011 is incorporated by referenced herein. 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           10  Insertion tongue 
           11  Insertion portion 
           11   a  Recess 
           12  Belt retention portion 
           13  Slot 
           13   a  Edge 
           13   b  Edge 
           14  End portion 
           20  Safety belt 
           30  Plastics strand 
           40  Webs 
           50  Teeth 
           60  Metal plate 
           70  Opening 
           80  Edge portion 
           81  Outer side 
           82  Deep-drawn portion 
           83  Bent portion 
           90  Plastics material 
           91  Plastics layer 
         R Extent direction 
         P 1  Arrow direction 
         P 2  Arrow direction