Abstract:
A frame (10) for a vehicle seat belt retractor comprises a back part (12), two side legs (16) extending in parallel to each other starting from the back part (12), with a retaining aperture (18) for a belt reel being provided in each side leg (16), and a mounting structure for mounting the frame (10) fixed to the vehicle, wherein the mounting structure includes a retaining bracket (22) having a mounting hole (36) for a retaining means (50) and at least one deformable deformation element (46). Furthermore, in accordance with the invention a vehicle structure for mounting a belt retractor in a vehicle is provided comprising a body part (52) and a frame (10) according to the invention. Moreover, a sheet metal blank for such frame is provided.

Description:
RELATED APPLICATIONS 
       [0001]    This application corresponds to PCT/EP2O15/000077, filed Jan. 19, 2015, which claims the benefit of German Application No. 10 2014 001 167.4, filed Jan. 31, 2014, the subject matter of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to a frame for a vehicle seat belt retractor comprising a back part and two side legs extending in parallel to each other starting from the back part, wherein a retaining aperture for a belt reel is provided in each side leg. The invention further relates to a vehicle structure for mounting a belt retractor in a vehicle as well as a sheet metal blank for a frame of a vehicle seat belt retractor. 
         [0003]    Belt retractors comprising a back wall the surface of which contacts the vehicle body and is mounted thereto are known from the state of the art. The side legs on which the belt reel is supported extend at right angles away from said back wall, i.e. also at right angles from the vehicle body. Such frame is made in one piece from a sheet metal with the side legs being bent at right angles with respect to the back part. For this constructional design large sheet thicknesses of more than 2 mm are required, however, so as to ensure sufficient stability of the frame. 
         [0004]    For reducing the sheet thicknesses of such frame from the state of the art frames are known in which the back wall is offset by 90° vis-à-vis the vehicle body so that it extends away from the vehicle body. On the back wall a retaining bracket is provided which is bent so that its surface contacts the vehicle body. In addition, a retaining fitting that serves for stiffening the retractor and the retaining bracket is provided. This design helps to reduce the sheet thicknesses to 1.7 mm, wherein additional lands are required between the side legs so as to ensure the stability of this frame. 
       SUMMARY OF THE INVENTION 
       [0005]    It is the object of the invention to provide a frame for a vehicle seat belt retractor that has a smaller sheet thickness and nevertheless satisfies the necessary stability requirements. It is a further object of the invention to provide a vehicle structure for mounting a belt retractor in a vehicle which has a lower weight as well as a sheet metal blank for a frame by which material-saving manufacture of a frame for a seat belt retractor is possible. 
         [0006]    For achieving the object a frame for a vehicle seat belt retractor is provided comprising a back part, two side legs extending in parallel to each other starting from the back part, wherein a retaining aperture for a belt reel is provided in each side leg, and comprising a mounting structure for mounting the frame fixed to the vehicle, wherein the mounting structure includes a retaining bracket having a mounting hole for a retaining means and at least one deformable deformation element. The frames known from the state of the art are fully adjacent to the vehicle body. The forces occurring in a case of restraint have to be fully absorbed by the frame; therefore the latter has to be designed to be very stiff. The frame according to the invention is based on the consideration to absorb the load peaks at the beginning of the restraining operation by a deformation of the mounting structure. Only after deformation of the frame the load is completely transferred from the frame to the vehicle body. Since the deformation element is provided on the mounting structure, at the beginning of the restraining operation initially only said mounting structure but not the entire frame is deformed so that the function of the frame is maintained. 
         [0007]    Preferably, with such frame the retaining bracket is arranged on a free edge of the back part and is bent especially at right angles relative thereto so that the surface of the back part cannot fully contact the vehicle body. Full-surface contact of the frame to the vehicle body would impair deformation of the mounting structure. When the deformation element is deformed it is also possible that the angle between the back part and the retaining bracket varies and thus the back part is bent up relative to the retaining bracket. 
         [0008]    In order to fasten the frame additionally to the vehicle body a mounting hook especially projecting at right angles which engages in a corresponding hole on the vehicle body may be provided at the retaining bracket. 
         [0009]    Preferably the back part, the side legs and the retaining bracket are integrally formed of a sheet metal, wherein the side legs and the retaining bracket are bent at right angles relative to the back part. Thus the frame includes as few components as possible so that simple and quick fabrication of the frame is possible. The frame may be manufactured, for example, of a punched sheet metal blank. 
         [0010]    The deformation element may be arranged at a distance from the retaining bracket and may include a contact surface located in a plane with the retaining bracket. In this embodiment it is possible that merely the retaining bracket and the deformation element are adjacent to the vehicle body. The deformation element is arranged so that, when the webbing is tensioned, compressive formed is exerted against the vehicle body on the deformation element. The deformation element is deformed with the side legs and the back part being tilted about the retaining bracket. Consequently, in this embodiment the frame is swiveled about the retaining bracket and the first load peak is taken up by deformation of the deformation element. The deformation element may as well be configured so that it is not moved against the vehicle body and does not contact the latter before load is applied. 
         [0011]    In order to achieve a preferably high load bearing capacity by the deformation element, the retaining bracket is preferably located at a first end of the frame and the deformation element is located at a second end. In particular, the deformation element is provided in the unwinding direction of the webbing ahead of the retaining bracket so that, when tensile force is applied to the webbing, the deformation element is forced against file vehicle body. 
         [0012]    For preventing the side legs of the frame from contacting the vehicle body end thus fern affecting the deformation of the deformation element, the frame and especially the side legs are cot out between the retaining bracket and the deformation element. This ensures that the frame contacts the vehicle body only by the support element and the retaining bracket, i.e. the mounting structure. Especially the degree of deformation of the deformation element may also be affected by the geometry of the cutout. The deformation element may deform, for example, until the side legs or other parts of the frame contact the vehicle body, support the latter and in this way prevent or inhibit any further deformation of the deformation element. 
         [0013]    In addition, a guide plate having a guide slot for the webbing may be provided on the frame. The guide plate is arranged, for example, on the side legs opposite to the back part so that the frame is additionally reinforced by the guide plate. The guide slot is located opposite to a plane formed by the retaining bracket, especially with respect to the retaining apertures for the belt reel, for instance with respect to the belt reel substantially radially opposite to the retaining bracket. The guide plate stiffens the frame and offers a mounting facility for the guide slot. The guide slot is spaced apart from the vehicle body so that the webbing is unwound in the case of blocking of the belt reel so that a compressive force acts on the deformation element. The guide element may be a separate component being mounted on the side legs after bending the latter. This facilitates the manufacture of a sheet metal blank, for example, as the design of the latter may be less complex. 
         [0014]    The deformation element may be arranged on the guide plate, for Instance, so that the compressive force which is exerted on the webbing and on the frame, respectively, by the webbing contacting the guide slot may act directly on the deformation element via the guide element. Especially, the deformation element is formed by a bent edge of the guide plate. 
         [0015]    A deformation element may equally be provided between the back part and the retaining bracket. The deformation element is deformed upon swivellng the frame about the retaining bracket and in this way can equally reduce a load peak. It is in particular also imaginable that the frame merely includes said second deformation element between the back part and the retaining bracket so that, apart from the retaining bracket, no other contact point of the frame is required on the vehicle body. 
         [0016]    In order to increase the stability of the back part and/or of the side legs embossed patterns may be provided on the same so that they exhibit higher bending stiffness. 
         [0017]    For achieving the object, moreover a vehicle structure for mounting a belt retractor in a vehicle is provided comprising a body part and a frame according to the invention, the retaining bracket and the deformation element being assigned to the body part. At an unloaded distance the deformation element may be arranged at a distance from the vehicle body and may be moved against the latter and contact the latter only when a tensile force acts on the frame. 
         [0018]    Preferably the deformation element is arranged in a direction of unwinding the webbing at a distance from the retaining bracket and ahead of the same so that a compressive force may act on the deformation element when a tensile force is applied to the webbing while the belt reel is blocked. 
         [0019]    Furthermore, for achieving the object a sheet metal blank for a frame according to the invention is provided, the sheet metal blank including a back part portion, a retaining bracket portion as well as two side leg portions. The side leg portions are provided at opposed edges of the back part portions and the retaining bracket portion is provided at an edge extending between said opposed edges. Between the side leg portions a recess having dimensions larger than those of the retaining bracket portion is formed. The frame is preferably punched out of a plane sheet metal part. The sheet metal blank according to the invention permits reducing the waste when plural such sheet metal blanks are punched out. Since the recess is larger than a retaining bracket portion, the retaining bracket portion of a neighboring sheet metal blank may extend into said recess so that plural sheet metal blanks can be arranged in a very space-saving manner relative to each other on a sheet metal part. 
         [0020]    In such sheet metal blank a mounting hook formed by a punched cutout of the back part portion is provided at the retaining bracket portion. The mounting hook is bent relative to the back part portion and the retaining bracket portion so that it projects at right angles on the back side of the frame and can be mounted in a vehicle body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    Further advantages and features are evident from the following description in connection with the enclosed drawings. In which: 
           [0022]      FIG. 1  shows a perspective view of a frame according to the invention, 
           [0023]      FIG. 2  shows a second perspective view of the frame of  FIG. 1 , 
           [0024]      FIG. 3  is a top view onto the frame of  FIG. 1 , 
           [0025]      FIG. 4  is a bottom view of the frame of  FIG. 1 , 
           [0026]      FIG. 6  is a front view of the frame of  FIG. 1 , 
           [0027]      FIG. 6  shows a side view of a vehicle structure according to the invention comprising the frame of  FIG. 1 , and 
           [0028]      FIG. 7  shows a sheet metal strip comprising two sheet metal blanks according to the invention for the frame of  FIG. 1 . 
       
    
    
     DESCRIPTION 
       [0029]    In  FIGS. 1 to 5  a frame  10  for a vehicle seat belt retractor is illustrated. The frame  10  includes a back part  12  on which a side leg  16  is provided on each of opposite edges  14 . Each of the side legs  16  includes a retaining aperture  18  for a belt reel wherein a toothing  20  for blocking the belt reel is provided in the retaining aperture. For unwinding webbing the belt reel is rotated in a direction of rotation D. 
         [0030]    A retaining bracket  22  which is arranged at an edge  24  disposed between the edges  14  is moreover provided on the back part  12 . The frame  10  in addition includes a guide plate  26  on which a guide slot  28  is provided through which the webbing of the seat belt is guided. 
         [0031]    The back part  12 , the side legs  16  and the retaining bracket  22  are integrally fabricated of a sheet metal blank  30  shown in  FIG. 7 . The side legs  16  are bent at right angles with respect to the back part  12  and extend substantially in parallel to each other away from the back part  12 . The retaining bracket  22  is bent normal to the plane of the back part  12  and in the opposite direction with respect to the side legs  16  and equally extends substantially at right angles away from the back part  12 . 
         [0032]    The guide plate  26  is arranged opposite to the back part  12  at the side legs  16 . As is evident especially from  FIG. 2 , recesses  32  through which projections  34  provided at the edge of the side legs  16  extend are arranged at the guide plate  26 . The projections  34  are bent or caulked on the back side of the guide plate  26  so that the guide plate  26  is tightly connected to the side legs  16 . 
         [0033]    As is evident especially from  FIG. 1 , the retaining bracket  22  includes a mounting hole  36  for a retaining means  50  (see  FIG. 6 ) as well as a mounting hook  38  projecting at right angles which can get caught in a body part  52 , as will be explained hereinafter. The mounting hook  38  is formed by a punched cutout  40  of the back part  12 . 
         [0034]    On both the back part  12  and the side legs  16  embossed patterns  42 ,  44  are provided for increasing the stability of the back part  12  and the side legs  16 , respectively. 
         [0035]    Moreover, a deformation element  46  formed by a bent edge of the guide plate  26  is provided at the end of the guide plate  26  opposed to the guide slot  28 . The deformation element includes a contact surface  43  that is arranged in a plane including the retaining bracket  22 , as is visible especially from  FIG. 6 . 
         [0036]    The deformation element  46  forms a mounting structure for the frame  10  together with the retaining bracket  22 . 
         [0037]    As can be seen in  FIG. 6 , the frame  10  is attached to a body part  52  by a retaining means  50  extending through the retaining bracket  22 . The mounting hook  38  extends into an aperture  54  at the body part  52  and is fixed within the same. The deformation element  46  contacts the body part  52  with the contact surface  48  but is not fixed thereto. 
         [0038]    As the guide slot  28  of the guide plate  26  is arranged opposite to a plane formed by the retaining bracket  22  with respect to the retaining apertures  18 , the webbing is guided out of the frame  10  at a distance from the body part  52 . 
         [0039]    When a tensile force is exerted on the webbing with the belt reel being blocked, it acts vertically downwards, related to  FIG. 6 . Since the belt reel is fixed to the body part  52  by the retaining bracket  22  and by virtue of the distance of the guide slot  28  from the body part  52  a compression force F directed substantially perpendicularly against the body part  52  acts on the deformation element  46  and, respectively, on the contact surface  48 . Upon blocking of the belt reel this compression force F first causes the deformation element  46  to be deformed with the frame  10  being tilted about the retaining bracket  22 . This deformation helps to reduce the first load peak upon blocking of the belt reel so that lower load acts on the frame  10  and is transmitted to the body part  52  via the retaining means  50 . 
         [0040]    Other than with the frames known from the state of the art, part of the force acting on the frame  10  via the webbing is reduced through deformation of the frame  10  and, resp., of the mounting structure of the frame  10 . Since the other components of the frame  10  in this way have to absorb lower load, they may be configured to be thinner. Especially the sheet thickness may be reduced to 1.5 mm. As moreover a deformation of the frame  10  is desired, the latter need not be so stiff that it cannot deform. 
         [0041]    As is evident especially from  FIG. 6 , the deformation element  48  is arranged at a distance from the retaining bracket  22 , with the retaining bracket  22  being arranged in particular on a first end of the frame  10  and the deformation element  46  is arranged on a second end of the frame  10 . Due to this large distance between the retaining bracket  22  and the deformation element  46 , the force F can act on the deformation element  46  with an as large lever arm as possible so that the deformation element may be designed to be stiffer and may reduce higher load. 
         [0042]    Furthermore a recess  56  is formed at each of the side legs  16  between the retaining bracket  22  and the deformation element  46 . These recesses  56  prevent the side legs  16  from contacting the body part  52  and thus from inhibiting deformation of the deformation element  46 . In particular, the recesses  56  may be configured so that after defined deformation of the deformation element  46  the side legs  16  contact the body part  52  and prevent or inhibit further deformation of the deformation element  46 . 
         [0043]    By deforming the deformation element  46  and tilting the frame  10  also the back part  12  is bent relative to the retaining bracket  22 . For example, between the retaining bracket  22  and the back part  12  a second deformation element may be provided which is equally deformed by such bending-up. Said second deformation element may equally reduce a load peak by the deformation. 
         [0044]    Depending on the design of the frame  10  and, resp., of the vehicle structure, it is also possible that the lower end of the frame  10  with respect to  FIG. 6  does not contact a vehicle body  52 . In such embodiment also merely a second deformation element may be provided between the retaining bracket  22  and the back part  12 . 
         [0045]    In particular, the deformation element  46  of the mounting structure may be arranged at any position on the frame  10 . It has merely to be ensured that, when a tensile force acts on the frame  10 , the deformation element  46  is deformed by tilting, rotating, swiveling or displacing the frame  10 . 
         [0046]    As already afore-explained, the frame  10  is manufactured of a plane sheet metal blank  30  as well as the guide plate  26 .  FIG. 7  illustrates an example of such sheet metal blank  30  showing a sheet metal part  57  including several sheet metal blanks  30 . 
         [0047]    The sheet metal blank  30  comprises a back part portion  58 , two side leg portions  60  and a retaining bracket portion  62 . The side leg portions  60  are provided on opposite edges at the back part portion  58 , the retaining bracket portion  82  is located on an edge disposed between the opposite edges. The side leg portions  60  mostly extend in a direction opposed to the retaining bracket portion  62  so that a recess  64  is formed between the former. 
         [0048]    The dimensions of this recess  64  are larger than the dimensions of the retaining bracket portion  62 . In this way, as is evident from  FIG. 7 , the retaining bracket portion  62  of an adjacent sheet metal blank  30  may be arranged in the recess  64 . The side leg portions  60  of adjacent sheet metal blanks  30  and, hence, the adjacent sheet metal blanks  30  in this way can be arranged very closely to each other, thus enabling the sheet metal blanks  30  to be arranged on the sheet metal part  57  in a material-saving manner. The waste of material can be reduced, which allows achieving better utilization of material. 
         [0049]    As is visible especially in  FIG. 7 , on the retaining bracket portion  62  a mounting hook portion  66  formed by a punched cutout  68  of the back part portion  58  is provided. In this way, the mounting hook  38  may be formed integrally with the retaining bracket  22  so that it is connected to the retaining bracket  22  in a more stable manner.