Abstract:
A buckle assembly for a motor vehicle belt restraint system. The buckle assembly includes a mounting plate and a buckle strap carrying the buckle which is rotatably affixed to the mounting plate. A torsion spring acts on the buckle strap to rotationally bias it toward a desired position. The buckle assembly includes a retainer for maintaining the buckle strap in a mounting position, allowing convenient mounting of the device to the motor vehicle structure. Following mounting, the retainer is released to enable the buckle strap to move to its normal range of positions, allowing the buckle assembly to operate in its normal manner.

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to a motor vehicle seat belt occupant protection system, and particularly to a buckle assembly for use in such systems.  
       BACKGROUND OF THE INVENTION  
       [0002]     Modern motor vehicles are equipped with occupant impact protection systems. Various types of such systems are presently in use, including so-called active devices such as manually deployed seat belts, and passive restraint systems, such as inflatable air-bags, side curtains, etc. Even when passive restraints are provided, occupants of passenger motor vehicles are provided with an actively deployed seat belt system, typically involving a lap and shoulder belt combination. Seat belt webbing retractors mounted to the seat or body structure of the vehicle allow the seat belts to be extracted from and retracted into the retractors when they are being used, and stowed when not in use.  
         [0003]     Motor vehicle manufacturers are constantly striving to enhance the comfort and convenience afforded for vehicles occupants, as well as improving the esthetics of the motor vehicle interior. Various designs of seat belt assemblies are used, but generally they use a buckle positioned to the “bight” area or crease between the seat cushion and seat back. The lap and shoulder belt latch plate is fastened to the buckle when the belts are worn. In many designs, the buckle is attached to a short length of seat belt webbing. Unfortunately, buckles mounted in this manner often become lost under the seat cushion and inaccessible or difficult to access by the seat occupants. Other designs mount the buckle to rigid or semi-rigid stalks, such as plastic coated cables causing the buckle to be held in an upward protruding position. Although such designs provide buckle accessibility, the buckles may become an obstruction when not being used by an occupant, and their positioning negatively affects the esthetics of the vehicle interior.  
         [0004]     To address the shortcomings of prior art buckle mounting systems mentioned above, more recent generations of designs incorporate a buckle which is mounted to a hinge for pivoting motion. These designs are especially prevalent for second and third row occupant seat applications. In one example of such applications, when the seat belt latch plate is not attached to the buckle, the buckle lies in a folded position under the influence of a spring to lie within a pocket formed in the seat cushion. The buckle may be grasped by the user and rotated to an upward position within a range of pivoted positions where it is positioned to receive the latch plate. When the latch plate is disengaged from the buckle, the seat belt buckle recedes under the influence of a torsion spring into its stowed position in the pocket. This provides a trim and orderly appearance of the buckles when the seat is unoccupied.  
         [0005]     In other applications, a pivoting buckle assembly is used which is biased to an upward pivoted position to receive the latch plate (use position). The pivoting movement in such applications may be provided to accommodate folding seat backs or for other reasons. For use in folding seat back applications, the folding of a seat component may act on the pivoting buckle causing it to be folded toward a flat condition.  
         [0006]     The previously mentioned pivoting buckle assemblies are known in the prior art. Although they operate successfully, difficulties are encountered in mounting these devices during the assembly of the vehicle. In the position of the buckle established by the influence of a torsion spring, the mounting aperture and mounting fastener for the buckle mounting plate may not be readily accessed. In such instances, the assembly operator must pivot the buckle assembly against the torsion spring tension in order to gain access to the mounting fastener and aperture. This complicates the assembly process.  
         [0007]     In view of the foregoing, there is a need in the art to provide a pivotable buckle assembly for automotive restraint systems which can be maintained in a mounting position for convenient access for mounting features, yet can be actuated or released to a normal usage condition in which it is biased to a desired position under the influence of the torsion spring. Preferably, the device for providing such retention in the mounting position should not incorporate additional components or generate broken pieces which could remain in the vehicle and become a source of later problems.  
       SUMMARY OF THE INVENTION  
       [0008]     The buckle assembly in accordance with the present invention provides a retainer mechanism which enables the buckle strap to be maintained in a mounting condition until after installation, when it may be used in the normal manner enabling the buckle strap to move within its normal range of motion. Two distinct embodiments for retainer systems in accordance with this invention are described. In one embodiment, the retainer utilizes a bushing, preferably formed from a polymeric plastic material having two sections, each respectively coupled for rotation to the mounting bracket and buckle strap, and having a frangible connection between them. When the buckle is assembled, the parts are held in a mounting position, providing convenient mounting to the vehicle. Following mounting, the frangible connection is easily broken by forcing the buckle toward its normal range of positions. Once the frangible connection is broken, the buckle assembly operates in its normal manner, pivotable within its range of motion while biased by the torsion spring.  
         [0009]     In a second embodiment of a buckle assembly in accordance with this invention, a retainer mechanism is provided in which an end of the torsion biasing spring interacts with the mounting bracket in such a manner as to maintain the parts in a mounting position, yet can be actuated or released to allow the buckle to operate over the normal range of pivoted positions under the influence of the torsion spring.  
         [0010]     Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a pictorial view of a second row seat of a motor vehicle showing a buckle assembly in accordance with this invention for use with a lap and shoulder belt system illustrated in the unlatched, unused condition;  
         [0012]      FIG. 2  is a figure similar to  FIG. 1 , but showing the buckle assembly affixed to the latch plate and showing the buckle rotated to an upward pivoted usage position;  
         [0013]      FIG. 3  is a side view of the buckle assembly in accordance with a first embodiment of this invention adapted for use with the seat belt system shown in  FIGS. 1 and 2 ;  
         [0014]      FIG. 4  is a partial pictorial view of a first embodiment of a belt buckle assembly in accordance with this invention;  
         [0015]      FIG. 5  is a top view of the buckle assembly shown in  FIG. 4 ;  
         [0016]      FIG. 6  is a partial view of a subassembly of the buckle assembly shown in  FIGS. 4 and 5 ;  
         [0017]      FIG. 7  is a side view of the release bushing assembly used in the buckle assembly illustrated in the prior figures.  
         [0018]      FIG. 8  is a pictorial view of the bushing assembly shown in  FIG. 7 ;  
         [0019]      FIG. 9  is a side pictorial view illustrating the mounting strap and bushing components;  
         [0020]      FIGS. 10A and 10B  show the frangible connecting strips of the retainer bushing in an intact and failed conditions, respectively.  
         [0021]      FIG. 11  illustrates a buckle assembly providing a pair of buckles; and  
         [0022]      FIG. 12  is a pictorial view of the buckle assembly in accordance with a second embodiment of this invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]      FIGS. 1 and 2  illustrate the general environment of application of the present buckle assembly. As shown by those figures, buckle assembly  10  is shown positioned within cushion pocket  12  of a seat cushion  14 . Lap and shoulder belt assembly  16  includes an upper shoulder belt portion  18  and a lower lap belt portion  20 . The belt assembly  16  is fastened to buckle assembly  10  by affixing latch plate  22  within the buckle  24 . As shown, buckle assembly  10  is mounted adjacent the “bight” or crease area  26  between seat cushion  14  and seat back  28 .  
         [0024]      FIG. 1  illustrates buckle assembly  10  in its normal stowage position in which buckle  24  is pivoted forward and fits within cushion pocket  12 .  FIG. 2  illustrates the upward deflected position of buckle  24  when latch plate  22  is fastened to the buckle.  
         [0025]      FIG. 3  illustrates the basic components of buckle assembly  10 . Buckle assembly  10  generally comprises mounting bracket  30  with buckle strap  32  to which buckle  24  is attached. As shown, fastener  34  is used to fasten mounting bracket  30  to vehicle structure  36 . As shown by the figure, arrow  38  indicates that buckle strap  32 , with buckle  24 , are biased toward a forward rotated position in the direction of the arrow. In order to provide convenient access for a tool to engage mounting fastener  34 , it is necessary to rotate buckle  24  and buckle strap  32  to the upwardly deflected pivoted position shown in  FIG. 3 . Fastener  34  passes through mounting bracket aperture  35 . As mentioned previously, a principal feature of this invention is to accommodate such access and fastening.  
         [0026]     It should be noted that, in other applications, the position shown in  FIG. 3  may represent the normal position of buckle  24  established by the influence of the biasing spring, and access for fastening may require folding of the buckle in the direction of arrow  38  against spring torsion.  
         [0027]      FIGS. 4 through 10  illustrate in more detail buckle assembly  10  in accordance with the first embodiment of this invention. As illustrated, mounting bracket  30  features a pair of upstanding walls  42  and  44 . Buckle strap  32  incorporates a central hole  46  through which a pivot pin in the form of rivet  48  is installed. This arrangement allows buckle straps  32  to rotate relative to mounting bracket  30  about the rotational axis established by rivet  48 . Torsional coil spring  50  includes end  52  which engages mounting bracket  30  and opposing end  54  which engages with buckle strap  32  to provide the rotational biasing previously described.  
         [0028]     In accordance with a principal feature of this invention, buckle assembly  10  further features a retainer means in the form of retainer bushing  56 , best shown by  FIGS. 6, 7 , and  8 , which includes spaced apart washer-shaped retainer portions  58  and  60 , each forming hole  62  through which rivet  48  passes. Retainer portion  58  includes posts  64  which embrace buckle strap  32  so that both parts rotate together about rivet  48 . Retainer portion  60  includes ears  66  which engage with features of mounting bracket  30 , preventing the retainer portion  60  from rotating relative to the mounting bracket. Retainer bushing portions  58  and  60  are stacked against one another as shown in  FIGS. 7 and 8 . They are, however, maintained in a set relatively rotated indexed position by a pair of connecting straps  68  shown in  FIG. 10A . As illustrated in  FIG. 10A , connecting straps  68  includes a narrowed-down failure region  70  which, for purposes to be described below, is frangible or breakable when desired.  
         [0029]     The orientation of retainer bushing portions  58  and  60  is such that during assembly, buckle strap  32  is maintained in a particular indexed mounting position such as the positions illustrated in  FIGS. 3 and 4  in which the buckle strap and associated buckles  24  are rotated to an “open” position within its range of pivoted positions displaced from the stowage position against the biasing of spring  50 . This position allows access to aperture  35  and fastener  34 . Following the assembly process, buckle  24  may be urged forcibly toward a folded forward position which causes connecting strap failure region  70  to fail, as indicated in  FIG. 10B . Upon this failure, retainer portions  58  and  60  are no longer mechanically connected to rotate together, and thus buckle strap  32  is free to rotate relative to mounting bracket  30  under the influence of torsional spring  50  or externally applied forces. Thus, after buckle assembly  10  is “released” in this manner, it is able to operate in a normal mode, pivoting between the position shown in  FIG. 1  and to position within a range of pivoted positions, as shown in  FIG. 2 .  
         [0030]     As mentioned previously, the assembly position of buckle assembly  10  may be folded flat, to the position shown in  FIG. 4 . In such case, retainer bushing  56  maintains the buckle assembly in the position of  FIG. 4 , until it is released, enabling the buckle strap  32  to rotate upwardly under the influence of spring  50 .  
         [0031]     Preferably, the material selected for retainer bushing  56  does not produce loose parts when connecting strap  68  is caused to fail. Retainer bushing  56  is preferably formed as a unitary structure by injection molding or other processes using a polymeric resin or other material.  
         [0032]      FIG. 11  illustrates a buckle assembly  71  incorporating a pair of mounting straps  72  and  73 , for a pair of buckles  24 . Both mounting straps  72  and  73  may rotate together and use a single retainer bushing  56  as shown, or the straps could be independently pivotable, with separate retainer bushings provided for each. Buckle assembly  71  operates in a manner identical to buckle assembly  10 , except that two buckles  24  are provided. Components of buckle  71 , along with the additional embodiment illustrated by  FIG. 12  which are identical to components previously described, are identified by reference numbers used in the above description.  
         [0033]     Now with reference to  FIG. 12 , the second embodiment of buckle assembly  74  is illustrated. In the case of buckle assembly  74 , each buckle  24  is able to move independent of one another using separated buckle straps  76  and  78 . Buckle assembly  74  includes mounting bracket  80  and a pair of pivot pins in the form of rivets  82  and  84 . Torsional coil springs  86  and  88  are provided for rotational biasing in the manner as described in connection with the first embodiment. Each of coil springs  86  and  88  includes extending ends  90  and  92 , respectively, extending through apertures  94  and  96 , respectively. The other ends of coil springs  86  and  88  engage with mounting bracket  80  in the manner of the prior embodiment. Mounting bracket  80  sidewalls  98  and  100  include protruding projections or ears  102 .  
         [0034]     As illustrated in  FIG. 12 , spring ends  90  and  92  extend through apertures  94  and  96  in buckle strap  76  and  78 , and engage with ears  102  and  104 . This engagement causes buckle straps  76  and  78  to be maintained in the folded flat, pivoted mounting position shown in  FIG. 12  which provides convenient access for mounting as previously described. After assembly, buckles  24  may be forcibly moved toward the upward position, which is in the clockwise direction with regard to the orientation of elements shown in  FIG. 12 . This movement causes spring ends  90  and  92  to ride over ears  102 , allowing the coil springs  86  and  88  to bias their respective buckle straps  76  and  78  in a normal manner between the folded flat mounting position and upwardly pivoted positions within a range of positions, as explained in connection with the first embodiment. Coil springs  86  and  88  urge buckle straps  76  and  78  to a normal, use position which is upwardly pivoted.  
         [0035]     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.