Abstract:
An air bag cushion deployable from a location along the roof rail the vehicle interior over an expansive area adjacent to an occupant to be protected. The air bag cushion is of a partially segmented construction including a main body portion deployable downwardly away from the roof rail and an expansible upper portion expansible between the header portion of the roof rail and the head of an adjacently seated vehicle occupant. The main body portion and the inflatable upper portion of the air bag cushion are attachable to the roof rail structure along a common line of attachment. The inflatable upper portion and the main body portion of the air bag cushion may be inflated by a common source of inflation gas so as to utilize a single common inflator.

Description:
TECHNICAL FIELD 
     The present invention relates to an inflatable air bag cushion for use in covering a side portion of a vehicle interior adjacent to an occupant to be protected during a collision event, and more particularly, to an air bag cushion of substantially curtain-like structure for deployment away from the roof rail of the vehicle. The air bag cushion includes a main body portion for deployment generally downwardly and away from the vehicle roof rail to the side of an occupant to be protected and an inflatable upper portion for expansion between the head of the occupant to be protected and opposing portions of the roof rail structure. 
     BACKGROUND OF THE INVENTION 
     It is well known in motor vehicles to provide air bag cushions for protecting a vehicle occupant. Such air bag cushions are typically in fluid communication with gas generating inflators so as to inflate the cushions upon sensing predetermined vehicle conditions such as decelerations exceeding a certain level. It is further known to provide air bag systems including inflatable restraint cushions which are deployed from positions of attachment to the vehicle frame along the roof rail portion of the vehicle frame so as to extend downwardly in substantially curtain-like fashion between an occupant to be protected and the side portion adjacent to such occupant. Such coverage is intended to provide cushioning restraint for the occupant during a side impact or extended roll-over collision event. Such curtain-like structures thereby provide protection to the vehicle occupant generally in regions below the location of attachment along the roof rail of the vehicle. That is, the protection afforded by such downwardly deployed curtain-like structures extends substantially in the region below the zone of attachment along the roof rail. 
     In some instances such as during an extended roll-over event, it is contemplated that an occupant may come into contact with the upper portions of the roof rail structure commonly referred to as the “header” portion of the roof rail. Typically, such contact will be between the head of the vehicle occupant and the header portion of the roof rail which is generally undesirable. 
     SUMMARY OF THE INVENTION 
     This invention provides advantages and alternatives over the prior art by providing an air bag cushion which is deployed from a location along the roof rail portion of a vehicle frame in substantially curtain-like fashion across the side of the vehicle interior over an expansive area adjacent to an occupant to be protected. The air bag cushion further includes an expansible upper portion expansible between the header portion of the roof rail and the head of an adjacently seated vehicle occupant. The main body portion and the inflatable upper portion of the air bag cushion are attachable to the roof rail structure along a common line of attachment. The inflatable upper portion and the main body portion of the air bag cushion may be inflated by a common source of inflation gas so as to utilize a single common inflator. 
     According to one potentially preferred aspect of the invention, the air bag cushion incorporates a substantially segmented construction along at least a portion of its length such that the inflatable upper portion and the main body portion are separated from one another except for a common inflation path adjacent a gas inlet opening to the air bag cushion. The segmented construction of the air bag cushion facilitates potentially desirable attachment arrangements between the air bag cushion and the roof rail so as to promote desired deployment characteristics for the inflatable upper portion which are substantially independent from the inflation and deployment of the main body portion. 
     According to another potentially preferred aspect of the present invention, deployment of the inflatable upper portion of the air bag cushion is not dependent upon inflation of the main body portion since inflation gas is not required to travel substantially through the main body portion before reaching the inflatable upper portion of the air bag cushion. The present invention thus provides a highly efficient and versatile structure for providing cushioning protection to a vehicle occupant and thus provides useful advantages over the prior art. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A full and enabling disclosure of the present invention is set forth more particularly in the remainder of the specification, including reference to the accompanying figures in which: 
     FIG. 1 is a cut-away view of the interior of an automotive vehicle incorporating a curtain-like air bag cushion according to the present invention mounted along the roof rail portion of the vehicle frame generally to the side of and above an occupant to be protected; 
     FIG. 2 illustrates one embodiment of a curtain-like air bag cushion according to the present invention; 
     FIG. 3 is a representative view of an attachment arrangement between the air bag cushion illustrated in FIG.  2  and the roof rail portion of the vehicle frame; 
     FIG. 3A is a representative view of an attachment arrangement between the air bag cushion illustrated in FIG.  2  and the roof rail portion of the vehicle frame; 
     FIG. 4 is a representative view of the deployment of a curtain-like air bag cushion according to the present invention mounted using the attachment arrangement illustrated in FIG. 3; and 
     FIG. 4A is a representative view of the deployment of a curtain-like air bag cushion mounted incorporating the attachment arrangement illustrated in FIG.  3 A. 
    
    
     While the invention has been illustrated and generally described above and will hereinafter be described in connection with certain potentially preferred embodiments, constructions and practices, it is to be understood that in no event is the invention to be limited to such illustrated and described embodiments, constructions or practices. On the contrary, it is intended that the present invention shall extend to all alternatives and modifications as may embrace the broad principles of this invention within the true spirit and scope thereof. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings wherein like reference numerals have been utilized to designate like components throughout the various views, in FIG. 1, there is illustrated a vehicle  10  such as an automobile as will be well known to those of skill in the art. It is to be appreciated that while the invention will hereinafter be described in reference to operation within an automobile, it is contemplated that the invention is likewise applicable to any number of other transportation vehicles including by way of example only, aircraft, buses and railroad cars. In the illustrated environment of use, the vehicle  10  includes a front seat  12  which may be used to support a front seated vehicle occupant  14 . The vehicle  10  may further include a rear seat  16  which may be used to support a rear occupant (not shown). While the front seat  12  and the rear seat  16  are illustrated as being located on the driver&#39;s side of the vehicle  10 , it is to be appreciated that the present invention is also useful in the protection of an occupant (not shown) seated in either the front seat or rear seat on the passenger side of the vehicle  10 . 
     In order to provide visibility to the occupant  14 , the vehicle  10  is provided with a windshield  18  as well as with one or more side windows  20 . As illustrated, the side windows  20  are located generally adjacent to the seats  12 ,  16  to the sides of the occupants seated therein. The vehicle  10  preferably also includes one or more doors  22  which extend adjacent to the seats  12 ,  16  towards a roof  26 . 
     As will be appreciated by those of skill in the art, the vehicle  10  preferably includes a structural frame formed from an arrangement of structural support members including a roof rail  30  disposed generally at the intersection between the doors  22  and the roof  26 . The vehicle  10  also preferably includes a series of structural support members  32 ,  34 ,  36  which extend downwardly from the roof rail  30 . The structural support pillar  32  which extends between the windshield  18  and the side window  20  adjacent to the front seat  12  is commonly referred to as the “A” pillar. The structural support pillar  34  disposed intermediate the side windows  20  is commonly referred to as the “B” pillar. The structural support pillar  36  disposed rearward of the side window  20  adjacent to the rear seat  16  is commonly referred to as the “C” pillar. As will be appreciated, each of the structural support pillars  32 ,  34 ,  36  is preferably covered by a trim piece which extends in elongate fashion away from the roof rail  30 . The roof rail  30  is likewise preferably covered by a trim piece or headlining material  38  as shown in FIG. 4 so as to permit the egress of an air bag cushion in the manner as described hereinafter. 
     As illustrated in FIG. 1, it is contemplated that an air bag cushion in the form of an inflatable curtain structure  40  may be stored in rolled or folded fashion in attached relation to the vehicle frame along at least a portion of the roof rail  30 . It is also contemplated that portions of the inflatable curtain structure may be stored along portions of the “A” pillar  32  and/or along portions of the “C” pillar  36 . As shown, the inflatable curtain structure  40  is preferably in fluid communication with a gas discharging inflator  42 . As is well known to those of skill in the art such that gas may be discharged from the inflator  42  and into an inlet opening  44  (FIG. 2) to effect deployment of the inflatable curtain structure  40 . As illustrated, the inflatable curtain structure  40  may also be attached to tethering elements  46  secured at locations to promote the desired deployment path for the inflatable curtain structure upon inflation by the inflator  42 . As will be appreciated, the inflatable curtain structure  40 , inflator  42 , and tethering elements are preferably hidden from view by the overlying trim. 
     It is to be understood that while the inflatable curtain structure  40  is illustrated as being attached substantially between the “A” pillar  32  and the “C” pillar  36 , storage may in fact take place over either a longer or a shorter region if desired. By way of example only, in the event that the vehicle  10  incorporates only a front seat  12 , the inflatable curtain structure  40  may be attached between the “A” pillar  32  and the “B” pillar  34 . Likewise, in the event that the vehicle  10  incorporates additional rows of seats (not shown), the inflatable curtain structure may be attached between opposing pillar elements at either end of the vehicle  10 . Moreover, while the vehicle  10  is illustrated as incorporating only a single inflatable curtain structure  40  for coverage of the region adjacent to the seats  12 ,  16  it is likewise contemplated that two or more such curtain structures  40  may be utilized if desired to cooperatively cover portions of the vehicle interior. 
     Referring now to FIG. 2, an inflatable curtain structure  40  according to the present invention is illustrated. As previously indicated, the inflatable curtain structure  40  preferably includes a gas inlet opening  44  in fluid communication with the inflator  42  so as to permit the introduction of a gaseous inflation medium into the inflatable curtain structure  40  upon the occurrence of predetermined vehicle conditions such as rapid deceleration or angular tilt exceeding certain levels. According to the potentially preferred practice of the present invention, the inflatable curtain structure is formed by adjoining panels of substantially pliable material in a pattern so as to form a substantially gas tight enclosure to contain the inflation gas exiting the inflator  42  during an extended roll-over event. 
     As best illustrated through reference to FIG. 4, it is contemplated that the inflatable curtain structure  40  preferably includes a front impact surface  50  which faces towards the occupant  14  to be protected during a collision event and a rear surface  52  which faces generally away from the occupant to be protected during the collision event and toward the adjacent side window  20 . The front impact surface  50  and the rear surface  52  bound a gas containment chamber within the main body portion  54  of the inflatable curtain structure  40 . In addition, as best illustrated in FIG. 2, it is contemplated that the inflatable curtain structure  40  may include a pattern of regions of substantially non inflatable character  56  formed by joining together the front impact surface  50  and the rear surface  52  in areas where inflation is not desired thereby precluding expansion of the cushion in those regions and reducing the total volume of inflating gas necessary to achieve complete inflation. 
     The materials forming the inflatable curtain structure  40  are preferably of a substantially pliable character so as to permit the inflatable curtain structure  40  to be rolled or folded into a compact space beneath the trim  38  covering the roof rail  30 . Textile fabrics may be preferred. Woven or knitted fabrics of nylon or polyester may be particularly preferred. It is contemplated that the air bag cushion  40  may be formed from two or more substantially discrete panels of material which are thereafter seamed together or may be formed as a substantially unitary structure if desired. That is, since the air bag cushion  40  according to the present invention is of a relatively simple substantially two-dimensional configuration incorporating two opposing layers of material, it is possible to form the cushion using either traditional cutting and sewing techniques or by using patterned weaving or knitting techniques to form the air bag cushion  40  directly on the weaving loom or other formation apparatus simultaneous with the construction of the fabric or other material from which the air bag cushion is made. The ability to utilize such on loom formation may be beneficial in reducing processing steps and labor needed to form the air bag cushion  40 . Moreover, as explained further hereinafter, despite a relatively simple construction, the air bag cushion  40  is nonetheless capable of providing substantial coverage over a relatively complex geometric surface both above and below its position of attachment to the vehicle  10 . 
     In order to retain the inflating gas during an extended roll-over event, it is contemplated that the materials forming the inflatable curtain structure  40  are preferably substantially impermeable to the inflation gas. In this regard it is contemplated that such low gas permeability may be achieved by providing a permeability blocking coating in the form of a film or dispersion of suitable material such as silicone, polyurethane, polyamides, acrylics and mixtures thereof across the inflatable portions of the front impact surface  50  and the rear surface  52 . 
     As indicated, according to the illustrated and potentially preferred embodiment, the inflatable curtain structure  40  includes the inflatable main body portion  54  defining the gas containment chamber bounded between the front impact surface  50  and the rear surface  52 . As illustrated in FIG. 4, upon deployment, the main body portion  54  is deployed generally downwardly away from the roof rail  30 . As illustrated in FIG. 2, the inflatable curtain structure  40  also includes an inflatable upper portion  60 . The main body portion  54  is preferably separated from the inflatable upper portion  60  by a zone of separation  62  such as a gap extending along a portion of the length of the inflatable curtain structure  40 . As illustrated, the separation between the main body portion  54  and the inflatable upper portion  60  is preferably terminated at a location adjacent the inlet opening  44  such that both the main body portion  54  and the upper portion are in common fluid communication with the inlet opening  44 . Such common fluid communication facilitates the use of a single inflator  42  to inflate both the main body portion  54  and the inflatable upper portion  60 . However, inflation gas need not travel through the main body portion  54  in order to reach the upper portion  60 . Of course, it is to be appreciated that the main body portion  54  and the inflatable upper portion  60  may be separated by means other than a gap such as by a web structure or the like if desired. 
     As previously indicated, the inflatable curtain structure  40  is preferably attached to the frame of the vehicle  10  along a portion of the roof rail  30 . Referring simultaneously to FIGS. 2 and 3, according to one potential embodiment, the inflatable curtain structure  40  is provided with a first series of fastening apertures  64  arranged along the upper edge of the main body portion  54  adjacent the zone of separation  62  between the main body portion  54  and the inflatable upper portion  60 . A second series of corresponding fastening apertures  66  is preferably arranged along the lower edge of the inflatable upper portion  60  in substantially direct alignment with the first series thereby providing a dual set of fastening apertures  64 ,  66 . The incorporation of such a dual set of fastening apertures  64 ,  66  facilitates the mounting of the inflatable curtain structure  40  to the roof rail  30  so as to provide the ability to control the deployment orientation of the inflatable upper portion  60  without altering the deployment characteristics of the main body portion  54 . 
     As shown in FIG. 3, according to a first mounting arrangement, the inflatable upper portion  60  may be pulled towards the main body portion to effect substantial alignment between the fastening apertures  64 ,  66 . This alignment permits the insertion of a common fastening element  70  such as a screw or snap fastener through each aligned pair of fastening apertures  64 ,  66  for attachment to the roof rail  30 . Of course a plurality of such fastening elements  70  extending through corresponding pairs of fastening apertures  64 ,  66  is arranged along the attachment zone. As best illustrated in FIG. 4, the attachment arrangement utilized in FIG. 3 promotes the generally upward deployment of the inflatable upper portion  60  along the header portion of the roof rail  30 . 
     An alternative fastening arrangement is illustrated in FIG.  3 A. As shown, in this arrangement, the inflatable upper portion  60  is folded in substantially flap-like fashion in juxtaposed relation to the main body portion  54 . This folding operation is carried out so as to substantially align the corresponding fastening apertures  64 ,  66  of the main body portion  54  and inflatable upper portion  60  respectively. Such alignment permits the insertion of a single fastening element  70  for connection to the roof rail  30 . The resultant deployment characteristics of the attachment arrangement illustrated in FIG. 3A are illustrated in FIG.  4 A. As shown, the attachment arrangement of FIG. 3A causes the inflatable upper portion  60  to be biased outwardly in a more lateral position which may provide added cushioning in the region immediately opposing the position of attachment to the roof rail  30 . Such performance characteristics may be desirable in some instances depending upon the actual configuration of the roof rail  30 . Such versatility facilitates the use of common inflatable curtain structure designs over a broad range of vehicle types. 
     As illustrated in FIGS. 4 and 4A it is contemplated that the inflatable upper portion  60  of the inflatable curtain structure  40  may be arranged in stored relation along the roof rail  30  behind a covering layer of headlining material  38  such that it deploys from a position generally behind the headlining material  38 . As illustrated, such an arrangement forces the headlining material  38  away from the roof rail  30  during deployment. It is likewise contemplated that the inflatable upper portion  60  may be deployed in front of the headlining material  38  if desired. By way of example only, and not limitation, such deployment characteristics may be realized by storing the inflatable curtain structure  40  behind a roof rail trim element (not shown) which hinges downwardly and outwardly (i.e. towards the windows  20 ) as it is forced away from the roof rail  30  by the deploying inflatable curtain structure  40 . Such a configuration has the benefit of allowing the headlining material  38  to remain substantially intact during the deployment event which may provide additional coverage over the header portion of the roof rail  30 . 
     It is to be understood that while the present invention has been illustrated and described in relation to certain potentially preferred embodiments, constructions and procedures, that such embodiments, constructions and procedures are intended to be illustrative only and that the present invention is in no event to be limited thereto. Rather, it is contemplated that modification and variations embodying the principles of this invention will no doubt occur to those of skill in the art. It is thus contemplated and intended that the present invention shall extend to all such modifications and variations as may incorporate the broad aspects of the invention within the full spirit and scope of the appended claims and all equivalents thereto.