Abstract:
A seat belt buckle assembly has a buckle head having an attachment member and a strap comprising a predetermined length of flexible woven webbing material fastened to the attachment member and comprising a loop spaced from the attachment member. Two such buckle heads may be mounted to a mounting bracket for attachment to a vehicle and hook and loop fasteners may connect them back to back. This buckle head is more compact and versatile then previously known arrangements.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a seat belt buckle assembly, and is particularly applicable for use in the rear passenger seat of a vehicle.  
       BACKGROUND OF THE INVENTION  
       [0002]     Traditionally rear seat belt buckles are mounted to the floor pan of a vehicle and the buckle head is stowed in a pocket in the seat cushion. The mounting must be strong enough to withstand crash forces and the buckle head is usually attached to the floor pan mounting by a steel strap or cable. However, this can cause discomfort to a rear seat passenger particularly in certain seating positions. In addition the steel strap makes it more difficult to fold the seat down smoothly when access to a rear storage compartment is required because the steel inhibits the buckle from folding with the seat. Steel straps also do not flex easily around the side of a child seat resulting in the buckle being pulled at an offset angle and ultimately weakening the buckle mechanism and degrading its performance.  
         [0003]     It would be preferable to use a flexible material to attach the buckle head to the mounting but a very strong material is needed. The strong woven webbing traditionally used for the seat belt itself has been tried but it has not been satisfactory because traditional arrangements require a minimum length of at least 200 mm to ensure sufficient space to attach the webbing to both the buckle head and the mounting effectively and safely, and this tends to be too long to allow the strap to fit easily into the stow pocket.  
       SUMMARY OF THE INVENTION  
       [0004]     According to the present invention there is provided a seat belt buckle assembly comprising a buckle head having an attachment member and a strap comprising a length of flexible woven webbing material having a first end fastened to the attachment member and a second end comprising a loop for attachment to a vehicle. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]     For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made to the accompanying drawings.  
         [0006]      FIG. 1  shows a traditional buckle arrangement.  
         [0007]      FIG. 2  shows a buckle arrangement according to one embodiment of the present invention.  
         [0008]      FIG. 3  shows the buckle arrangement of  FIG. 2  fastened to a bracket.  
         [0009]      FIG. 4  is a schematic diagram of two buckle arrangements fastened to a bracket.  
         [0010]      FIG. 5  shows the buckle arrangement of  FIG. 2  fastened to a floor pan.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]     In the known arrangement of  FIG. 1 a  buckle head  1  is shown attached to a buckle attachment bracket  2  and connected to a vehicle mounting bracket  3  by a strap comprising a length of traditional seat belt webbing  4 . The webbing  4  passes through holes in each of the two brackets  2 ,  3  and is stitched through three layers in a stitch pattern  5 . The webbing  4  is wider than the buckle head  1  and the mounting brackets and is folded across its width in the region of the brackets so that it fits through the holes. This restricts movement of the buckle head  1  in a lateral direction and limits the space available for the stitch pattern  5 . Traditionally the webbing  4  is about 48 mm wide and about 1.15 mm thick. The stitches in the stitch patterns would typically be about 37 mm long in the direction of weft fibres, i.e. across the webbing, and about 28 mm in the warp direction (along the webbing length) and the pattern comprises ten rows each of ten or eleven stitches across the webbing and one line of stitches in the length direction.  
         [0012]     The mounting bracket  3  has a second hole to which a similar arrangement is attached to form a double buckle head arrangement for attachment to the middle of a rear passenger seat in a vehicle. The mounting bracket  3  also has a hole  25  therethrough used for attaching it to the vehicle, for example with a bolt. The minimum overall length of such a known arrangement from the top of the buckle head to the mounting bracket is 200 mm.  
         [0013]     The new design can be seen in  FIGS. 2, 3 ,  4  and  5 . The buckle head  1  is attached to a length of webbing  4  via a buckle attachment bracket  2 , in the base of the buckle head  1 , through which the webbing  4  passes. The webbing  4  is then folded to form a loop  10  at an end opposite to the buckle head  1  and fixed in this configuration by stitching through the three layers at  11 . The webbing  4  in this embodiment is much narrower and thicker than in the arrangement of  FIG. 1 . Preferably the strap is formed of webbing which is around half the normal width of seat belt webbing, i.e. in a range of about 20 mm to about 30 mm, preferably about 25 mm wide instead of the usual 48 mm. This results in an overall length for the assembly of less than 140 mm, and even around 130 mm, which compares favourably with the previous minimum of 200 mm achieved with traditional webbing. The width of the webbing used in the present invention is less than the width of the buckle head, and about the same width as the hole in the attachment brackets  2 . According to a preferred embodiment the strap thickness is about twice that of traditional seat belt webbing, i.e. about 1.8 mm to about 2.5 mm preferably about 2.3 mm instead of the 1.15 mm of traditional seat belt webbing. The attachment bracket  2  in  FIG. 2  is effectively integral with the buckle head  1 .  
         [0014]     The stitch pattern  11  comprises a grid of ten stitches and ten rows. The length of the stitches used to secure the webbing strap is preferably about 14 mm to about 20 mm and even more preferably about 16 mm to about 18 mm and most preferably about 17 mm. This is in contrast to stitches in traditional seat belt webbing which have been around 37 mm across the webbing (in the weft direction) and 28 mm along the webbing (in the warp direction). This arrangement allows the overall length of the buckle arrangement to be particularly short: at least about 140 mm or about 130 mm.  
         [0015]     In the embodiment of  FIGS. 3 and 4  the assembly includes a pin  13  passing through the loop  10  for attachment to a vehicle, for example by lugs to a bracket such as a sill end bracket  12  that is attached to a load bearing part of the vehicle. The buckle is fastened to the vehicle by insertion of the loop  10  through a slot in a sill end bracket  12  and insertion of a steel pin  13  through the loop  10  as seen in  FIG. 3 . The steel pin  13  is then secured in place by lugs from the sill end bracket  12  and although not illustrated it will be evident to a person skilled in the art how this would be done. The loop may alternatively be fastened directly to the floor pan of a vehicle.  
         [0016]     In the embodiment of  FIG. 5  the loop  10  is directly fastened to the floor pan  20  of a vehicle by insertion through a slot  21  in the floor pan, insertion of the pin  13  in the loop  10  guided by location windows  22  and fixing the pin  13  in place by plastic attachment housing members  23  (only one of which is shown) on each side of the pin  13 . The attachment housing members  23  have securing features  24  that interact with complementary features in the floor pan  20 . For example upstanding lugs on the attachment housing  23  may fit into the location windows  22  on the floor pan  20  to hold the pin  13 .  
         [0017]     This new arrangement is strong, compact, flexible and versatile allowing substantial movement of the buckle head while securely restraining it.  
         [0018]     Two buckle heads may be mounted to a single mounting bracket by passing the loops through holes in the bracket and inserting a pin through each loop. In  FIG. 4 a  schematic view is shown of a double mounting bracket  14  to which two buckle heads  1 A,  1 B are attached by means of this new arrangement. Webbing straps  4  are stitched in the configuration shown in  FIG. 2  connected to respective buckle heads  1 A,  1 B at one end and formed with a respective loop  10 A,  10 B at each other end. The loops  10 A,  10 B are fed through slots or holes in the bracket  14  and respective steel pins  13 A,  13 B inserted into the loops  10 A,  10 B to secure the buckle heads in place.  
         [0019]     Complementary re-usable fastening sections, such as hook and loop fastening materials may be attached to sides of the buckle heads  1 . This may for example be the proprietary material known as VELCRO®, or any other re-usable fastening material. When the buckle arrangement is fixed in place in the vehicle, these fastening materials allow the two buckle heads to be fastened together and thus to sit up vertically above seat pads so as to present the buckle head opening in a more convenient position for the passenger to insert the buckle tongue. This is encouraged by the compact nature of the arrangement and the relative rigidity of the straps in the length direction. In the previously known arrangement shown in  FIG. 1  the arrangement did not easily sit up vertically and tended to get lost between seat pads.  
         [0020]     The vehicle mounting brackets  12 ,  14  may already be fixed in a vehicle when the buckles are attached or may be fixed subsequently, for example by means of a bolt through a hole in the bracket. In the embodiment of  FIG. 4  such a hole may typically be provided in the region  15  between the buckle attachment slots.  
         [0021]     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.