Abstract:
The present invention relates to a side curtain air bag safety device that protects a vehicle occupant from expansion of the air bag when the occupant is not in a desired position in the vehicle. The air bag includes an internal tether that is connected to a valve at the end of a throat liner within the bag. When the air bag expands and when the occupant is in a desired position, the tether extends fully and triggers the valve such that inflation gas is directed in a usual direction providing cushioning adjacent to the occupant. However, when the occupant is not in a desired position the tether cannot fully extend and as a result the expansion gas is directed in an alternate direction that does not apply as much force within the bag in an area near the occupant, thus preventing injury.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Side curtain air bags are a relatively modern vehicle improvement that significantly increases occupant safety. These air bags extend on the vehicle interior from a hidden location on the roofline downward, when inflated during a collision, to provide protection for a vehicle occupant. Side curtain air bags can improve safety significantly because they are often the only protection provided that is specific for side impact collision events or sideways movement of a vehicle occupant. A single air bag may cover, on one side of the vehicle, only the area where a front occupant is seated or both this area and the area where a rear occupant is seated. 
         [0002]    Side curtain air bags typically have a larger inflated volume than other air bag devices in the vehicle. However, inflation of side curtain air bags must still be as instantaneous as possible. To achieve this goal, higher flow rate inflators and/or multiple inflators may be used. Additionally, distribution devices such a throat liners are used to optimally distribute the inflation gas along the length of the air bag so that inflation is fast and generally even. Typically, larger volumes of air are directed to areas farther from the inflator to compensate for the increased time required for gas to reach these areas. 
         [0003]    Because side curtain air bags cannot inflate instantaneously, it is possible that the vehicle occupant, sliding laterally during a collision, could be located directly under the air bag as it expands downward from the roofline of the vehicle. The occupant could also be located in this position for other reasons. Either way, instead of being cushioned by the air bag, the occupant could be injured by the expanding air bag forcefully pushing on the top of his/her head. What is desired is a way to protect a occupant already located in an undesirable position when a side curtain airbag has not yet fully expanded into that position. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    The present invention relates to an air bag safety device that protects a vehicle occupant from downward expansion of the air bag when the occupant is not in a desired position in the vehicle. The air bag includes an internal tether that is connected to a valve. When the air bag expands and the occupant is in a desired position, the tether extends until becoming taut and triggers the valve such that inflation gas is directed in a usual direction into a chamber or chambers within the air bag adjacent to the desired position of the occupant. However, when the occupant is not in a desired position the tether cannot fully extend and as a result a larger volume of the expansion gas is directed in an alternate direction into an adjacent chamber not directly aligned with the occupant, which does not result in the generation of as much force within the bag chamber(s) in an area near the occupant. The invention is preferably installed within a side curtain air bag and the valve is at the distal end of a throat liner within the air bag (the throat liner&#39;s proximal end being near where an inflator attaches to the throat liner). In normal operation, inflation gas air passes through both the valve into the end of the air bag and aperture(s) in the bottom of the throat liner, but after closing the valve the gas passes only through the apertures in the bottom of the throat liner. 
         [0005]    The air bag safety device requires only two chambers within the air bag, one adjacent to the occupant and one not generally adjacent to the occupant, but typically the air bag is divided into three or more chambers as illustrated in the figures. These and other aspects of the invention are herein described in particularized detail with reference to the accompanying figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a side elevational view of an air bag system of the present invention with the air bag beginning to deploy; 
           [0007]      FIG. 2  is a side elevational view of the air bag system of the present invention in an partially (approximately two-thirds) expanded position when no occupant interference occurs; and 
           [0008]      FIG. 3  is a side elevational view of the air bag system of the present invention in an expanded position when no occupant interference occurs; and 
           [0009]      FIG. 4  is a side elevational view of the air bag system of the present invention in an expanded position when occupant interference occurs. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0010]    Referring to the drawings, specifically  FIGS. 2-3 , a preferred side curtain air bag system  10  according to the present invention is illustrated. The air bag system  10 , as described below, includes an air bag  12  divided into at least first and second chambers  14  and  16 , a throat liner  20  including a plurality of apertures  22 ,  24 ,  26  through which inflation gas exits the throat liner  20 , a valve  28 , and a tether  30  that actuates the valve  28 . The air bag system  10  is adapted to be placed in fluid communication with an inflator  32  that supplies inflation gas through the throat liner  20  into the air bag  12 . 
         [0011]    Referring to  FIG. 3 , the air bag  12  includes a gas receiving portion  34  and a border portion  36 . Preferably, the perimeter of the gas receiving portion  34  is fully surrounded by the border portion  36 . The border portion  36  of the air bag  12  has a thickness similar to the gas receiving portion  34  when the latter is not yet inflated. However, when the gas receiving portion  34  is inflated, the thickness of the gas receiving portion  34  increases significantly while the border portion  36  does not. The border portion  36  defines the rectangular shape of the air bag  12  when the air bag  12  is fully unrolled. 
         [0012]    The air bag  12  preferably is formed from two walls  40  and  42  that are laminated together in some areas, but not in others. Within the border portion  36  of the air bag  12 , the first wall  40  is laminated to the second wall  42 . However, in the gas receiving portion  34  of the air bag  12 , the first and second walls  40  and  42  are not laminated together and thus inflation gas is readily received therein. 
         [0013]    The gas receiving portion  34  of the air bag  12  has a generally rectangular shape with an additional narrow throat  38  that extends from an upper and rearward edge toward a source of inflation gas  32 . The gas receiving portion  34  is formed of at least the first wall  40  and the second wall  42 . When the air bag  12  is installed on a vehicle and expanding, the first wall  40  is closest to the center of the vehicle passenger compartment and the second wall  42  is closest to the vehicle door(s). The throat  38  has a diameter greater than a throat liner  20  that is placed therein. 
         [0014]    The rectangular part of the gas receiving portion  34  is divided at least into first and second chambers  14  and  16  (also referred to as cells), but preferably also includes a third chamber  18 . The chambers  14 ,  16  and  18  are defined in part by partitions  44  and  46  that run vertically with regard to the orientation of the air bag  12  when installed in a vehicle. Each partition is secured along one lengthwise edge to the first wall  40  of the gas receiving portion  34  and on a second, opposite lengthwise edge to the second wall  42  of the gas receiving portion  34 . Preferably, the partitions  44  and  46  are laminated to the walls  40  and  42  of the air bag  12 . 
         [0015]    In a preferred embodiment of the invention, the partitions  44  and  46  do not extend all the way to a top edge or a bottom edge of the gas receiving portion  34  of the bag  12 . Thus, gas can move between the chambers via gaps  50  near the top of the gas receiving portion  34  at any time when the air bag  12  is being filled and via gaps  50  at the bottom of the gas receiving portion  34  only when the bag  12  is almost completely filled. 
         [0016]    The first chamber  14 , defined in part by a first partition  44 , is located between a distal edge  52  of the gas receiving portion  34  of the air bag  12  and the first partition  44 . The second chamber  16  is located between the first partition  44  and an adjacent second partition  46 . The third chamber  18  is located between the second partition  46  and the proximal edge  54  of the gas receiving portion of the air bag  12 . 
         [0017]    A tether  30  is also located within the gas receiving portion  34  of the air bag  12 . The tether  30  is a cord that is used to actuate the valve  28 . The tether  30  is attached at a first end  56  on or near the bottom edge of the gas receiving portion  34  of the air bag. The tether  30  is attached at a second, opposite end  58  to the valve  28 . 
         [0018]    The throat liner  20  is a cloth tube attached, preferably by sewing, to the air bag  12  at the distal end of the throat liner  20 . The throat liner  20  includes a plurality of apertures  22 ,  24 ,  26  placed therein. The throat liner  20  fits within the gas receiving portion  34  of the air bag  12 , in the throat  38  and extends into the rectangular portion. The throat liner  20  extends from a connection point  60  with the inflator in a forward direction to a point above the first chamber  14  of the gas receiving  34  portion of the air bag  12 . The throat liner  20  also extends in a rearward direction from the connection point  60  with the inflator  32  if the air bag  12  has a portion for protecting occupants in the rear seat. 
         [0019]    The valve  28  is attached to the throat liner  20  at its distal end  62 . The valve  28  is any type of valve that may be actuated by a cord. The valve  28 , when closed, prevents the flow of gas out of the distal end  62  of the throat liner  20 . Alternatively, the valve  28  may be partially, but not fully closed by the actuation of the tether  30 , thus reducing, but not eliminating flow through the distal end  62  of the throat liner  20 . The throat liner  20  has a first aperture  22  at it distal end  62  through which the gas passes. Preferably, the throat liner  20  includes additional apertures  24 ,  26  on its bottom side. One aperture  24  is located above the second chamber  16  and another aperture  26  is located above the third chamber  18 . Preferably, the apertures are round, but may be other shapes as well. 
         [0020]    Referring to  FIGS. 1-3 , operation of the side curtain air bag system  10  is shown when the vehicle occupant is in a desired, safe position. Extreme motion of the vehicle or another trigger known in the art triggers the air bag system  10  and actuates an inflator  32 . Inflating gas is discharged from the inflator  32  into the throat liner  20 . As seen in  FIG. 1 , gas passes through the throat liner  20  and exits from apertures  22 ,  24  and  26 . The first aperture  22  is at the end of the throat liner  20  and second and third apertures  24 ,  26  are on the bottom side of the throat liner  20 . Approximately, the same amount of inflating gas exits from each aperture on the throat liner. As seen in  FIG. 2 , the tether  30  becomes taut when the air bag  12  is approximately ninety percent of the way unrolled. At this time, tension in the tether  30  pulls on the valve  28  causing it to close partially or fully. Thus, more inflating gas is directed to the second and third apertures  24 ,  26  of the throat liner  20 . As a result, the second and third chambers  16  and  18  of the expansion part  34  of the air bag  12  expand faster. As the air bag  12  unrolls to its full extent the tether  30  stretches slightly. 
         [0021]    In an alternate inflation scenario illustrated in  FIGS. 1 and 4 , the occupants head is not in a safe position, but is instead close to the vehicle door and in the path of the expanding air bag  12 . The air bag  12  begins unrolling in a manner identical to the prior scenario as shown in  FIG. 1 . However, the air bag  12  is unable to unroll into a position where the tether  30  is made taut. Instead, when the air bag  12  unrolls approximately half way, the top of the air bag  12  contact the occupants head. Thus, the valve  28  remains open and gas continues to be expelled into the first chamber  14 , as well as the second  16  and third  18  chambers. As a result, less force is applied to the occupant&#39;s head than in the first scenario described. Additionally, instead of forcing the second and third chambers  16  and  18  to further expand, inflation gas moves through the gaps  50  between the partitions  44  and  46  and the throat liner  20  from the second and third apertures  24 ,  26  into the first chamber  14 . This also prevents a significant amount of force is not applied to the occupant&#39;s head. 
         [0022]    The present invention provides a significant advantages over the prior art because extreme forces are not applied to a vehicle occupant&#39;s head during side curtain air bag inflation when the occupant is located in an undesired location that is close to the vehicle door. Further, the present invention uses a simple tether and valve system, optionally along with the special placement of partitions to achieve desired gas distribution when the occupant is in this position. No complex electronics or sensors are required to determine the occupant&#39;s position. 
         [0023]    As opposed to having two apertures on the bottom of the throat liner, as illustrated, only one or more than two apertures may be used. In conjunction with changing the number of apertures on the throat liner, the number of chambers within the gas expansion portion of the air bag may be increased or decreased. The shape of the side curtain air bag may also be changed and/or the shape and size of just the border portion or expansion portion. 
         [0024]    The length of the partitions may be varied, thus changing the size of the gaps between the chambers. These changes are based on testing and tuning to provide optimal gas flow within the expanding air bag. The partitions may be so long on its bottom as to reach the bottom edge of the gas receiving portion of the air bag. The partition may be so long on its top so as to reach the lower edge of the throat liner. 
         [0025]    The throat liner may extend to a rear air bag that protects occupant&#39;s in the rear seat of the vehicle. The structure of the air bag rear portion is similar to the front portion. 
         [0026]    Although the invention has been shown and described with reference to certain preferred and alternate embodiments, the invention is not limited to these specific embodiments. Minor variations and insubstantial differences in the various combinations of materials and methods of application may occur to those of ordinary skill in the art while remaining within the scope of the invention as claimed and equivalents.