Abstract:
A supplemental restraint assembly for a vehicle having a side impact air bag with an interwoven self-tensioning tether/lace. A side air bag is secured to the vehicle roof rail between the front and rear pillars. A tether/lace extends between and is secured to the front and rear pillars. The tether/lace is secured to the air bag and traverses a plurality of spaced-apart guides formed at discrete points along the air bag. When the side impact air bag is inflated the distance between the guides increases thereby taking up slack in the tether/lace thereby inducing tension therein. The air bag is thus held firmly in place when inflated and allows the tether/lace to be stored up through the pillars and along the roof rail in a non-deployed stored state.

Description:
FIELD OF THE INVENTION 
     This invention relates to a supplemental restraint assembly for an automotive vehicle and more particularly to a self-tensioning side impact air bag assembly. 
     DESCRIPTION OF THE RELATED ART 
     Air bags mounted in an instrument panel or steering wheel to protect an occupant from a front impact have become standard in the automotive industry. Numerous variations of these air bags, deployment systems and housing devices have evolved over the years. However, these frontal air bags do not provide protection to the occupant during a side impact. Recent developments have focussed on technology directed to side impact air bags and related systems. 
     Side impact air bag systems are also known in the art. These side impact air bags are often mounted adjacent the vehicle&#39;s roof rail, doorframe or center pillars, or in some instances within the side door. It is desirable to have tensioning to position the bag during side impact as well as any secondary events. 
     FIGS. 7A and 7B depict a side impact air bag  1  of the related art. The air bag  1  has a top edge  3  and a lower edge  4 . A front tether  5  and rear tether  6  connects the inflatable element  2  to corresponding front and rear pillars of an automotive vehicle. The top edge  3  has a plurality of mounting connections  7  for connection to the vehicle&#39;s roof rail. The air bag  1  may have a plurality of straight substantially square zero length tethers  8  extending from the lower edge  4  to the top edge  3 . FIG. 6B depicts the air bag of FIG. 6A in an inflated state. The inflatable element  2  shrinks when inflated and induces tension in the lower edge  4  and the tethers  5 ,  6 . This tension tends to hold the air bag  1  in place relative to the vehicle. However, the amount that the lower edge  4  may constrict is limited and therefore, the amount of tension and take up in the tethers  5 , 6  is limited to the amount that the lower edge  4  constricts during inflation. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an improved supplemental restraint assembly that improves upon the related art. 
     The present invention is directed to a side impact air bag with a self-tensioning tether/lace interlaced within the side air bag. A side air bag is secured to the vehicle along the roof rail between the front and rear pillars. A tether or lace is secured to the air bag and traverses a plurality of predetermined guide points. When the side impact air bag is inflated the distance between the guide points increases and any slack in the tether/lace is taken up. Thus the air bag is securely held in place when deployed. The side impact airbag, under some circumstances, serves to mitigate the threat of an occupant being ejected during a roll over event or subsequent impact. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevation view of a side impact air bag of the present invention mounted to an automotive vehicle in a stored position. 
     FIG. 2A is an elevation view of a side impact air bag according to one embodiment of the present invention mounted to a vehicle in a deployed non-inflated state. 
     FIG. 2B is an elevation view of the side impact air bag of FIG. 2A in an inflated state. 
     FIG. 3A is a cross sectional view of the side air bag of FIG. 2A taken along section lines  3 A— 3 A. 
     FIG. 3B is a cross sectional view of the side air bag of FIG. 2B taken along section lines  3 B— 3 B. 
     FIG. 3C is an elevational perspective view of the air bag of FIG.  2 B. 
     FIG. 4A is an exploded plan view of the bottom portion of the side air bag according to an alternative embodiment according to the present invention. 
     FIG. 4B is a cross sectional view of the air bag according to the alternate embodiment of FIG.  4 A. 
     FIG. 5A is a cross sectional view of the air bag according to an alternate embodiment in a deflated state. 
     FIG. 5B is a cross sectional view of the air bag of FIG. 5A by in an inflated state. 
     FIG. 5C is an elevational perspective view of the air bag of FIG.  5 B. 
     FIG. 6A is a cross sectional view of the air bag according to an alternate embodiment in a deflated state. 
     FIG. 6B is a cross sectional view of the air bag of FIG. 6A in an inflated state. 
     FIG. 6C is an elevational perspective view of the air bag of FIG.  6 B. 
     FIG. 7A is an elevation view of a side impact air bag of the related art in a non-inflated stated. 
     FIG. 7B is an elevation view of the side impact air bag of FIG. 6A in an inflated state 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is directed to an air bag of the present invention mounted to an automotive vehicle in a stored non-deployed state. An automobile  20 , has a front pillar  25 , a rear pillar  26  and a center pillar  23 . An air bag  1  is stored and mounted to the vehicle roof rail  24 . A front portion  31  of a tether/lace is connected to a front portion of the air bag  1  and to the front pillar  25 . A rear portion  32  of the tether/lace is connected to a rear portion of the air bag  1  and to the rear pillar  26 . The rear portion of the air bag  1  is connected to a gas generator  29 , or a duct leading from a gas generator to facilitate ingress of gas to the airbag  1 . 
     The air bag  1  is stored in a compartment mounted to the roof rail  24  as shown in FIG.  1 . Front and rear portions  31 , 32  of the tether/lace are also stored in a compartment in a corresponding pillar  25 ,  26 . When a side impact is detected, the air bag  1  is inflated by gas from generator  29 . As the air bag  1  inflates, it drops downward and is positioned and retained by the tethers  31 ,  32  as well as the point-wise mounting connections  7 . As gas fills the inflatable element  1 , the air bag  1  expands and a distance between a plurality of discretely positioned tether/lace guides increases. Thus, the length of the tether/lace required to span the length of the air bag  1  increases. Consequently, any slack in the tether/lace existing when the air bag  1  descends from its stored position is taken up by the expanding air bag  1  and the increased distance between the tether/lace guides. Note that the tethers  131 ,  132  are taut in the inflated state as shown in FIG.  2 B. The air bag  101  is thereby positioned between the occupant and the door or window opening to protect the occupant from side impacts and subsequent events, such as rollover or secondary impact. 
     FIGS. 2A-2B is directed to a side impact air bag  101  of the present invention. Preferably the front and rear portions  131 ,  132  of the tether/lace secures the air bag  1  between the A-pillar  125  and C-pillar  126  spanning the B-pillar  123 . However, the air bag  101  may be made to extend more rearwardly and secured to a D-pillar of a longer vehicle. Furthermore, the airbag  101  may be employed only in the forward compartment of the vehicle and connected to the A-pillar and B-pillars. It is preferred, however, to employ a single air bag  101  for both the front and rear passenger compartments, and therefore connect the inflatable element to the A-pillar (or front pillar  125 ) and the C-pillar (rear pillar  126 ). 
     The air bag  101  may be made of any suitable air bag material for holding gas, but is preferably made of a plurality of sheets of woven nylon fabric lined with urethane or other substantially impervious material such as silicone. The urethane coated nylon sheets are secured to one another along an outer periphery thereof to define the overall air bag shape. The sheets are connected along the pattern shown in dotted lines in FIGS. 2A-2B. Preferably, the nylon sheets are secured to one another by heating selected portions of the fabric dialectrically. The urethane or silicone coating of each of the two nylon sheets is laid against each other and together line the interior of the air bag  101 . The air bag  101  is then dialectrically treated to heat the outer causing the coating to adhere to one another. This forms a gas tight seal along the outer peripheral surface. The coated nylon sheets may also be stitched along the outer periphery to increase structural integrity sufficient to tolerate loads during inflation. When stitching is employed, it is preferred to treat the stitched area with a gas impervious substance to minimize gas leakage. Otherwise, the stress induced during inflation causes small holes in the stitching to widen and permit gas to escape thereby increasing deflation time. A bladder may also be used to line the inner surface of the air bag to maintain the air bag in an inflated state for a longer period of time. 
     The front and rear portions  131 ,  132  of the tether/lace form a part of a single woven cord or fabric laced about a plurality of discrete points on the air bag  101 . As the air bag  101  inflates, the distance between the discrete points increases and slack is taken up in the tether/lace. Note in the deflated state of FIG. 2A, the front and rear portions  131 ,  132  of the tether/lace are slack. However, when the air bag  101  is inflated as illustrated in FIG. 2B, any slack in the tether/lace between the front and rear portions  131 ,  132  is taken up and the tether/lace is taut thereby positioning the air bag  101  within the vehicle and holding the air bag  101  in place. The preferred embodiments for weaving the tether/lace about the air bag  101  will now be discussed. 
     FIG. 3A represents a cross sectional view of an air bag  201  in a deflated state. The air bag  201  is comprised of three panels  201   a ,  201   b , and  201   c  sewn together. An inboard panel  201   a , which faces the inner compartment of the vehicle, is sewn to an outboard panel  201   b  along a top edge  203  of the air bag  201 . A bottom panel  201   c  is sewn to each of the inboard  201   a  and outboard  201   b  panel forming a connection there between and defining the boundaries of the air bag  201 . A plurality of grommets  235  (tether/lace guides) are formed in a portion of the waste area outside of the stitching connecting the bottom panel  201   c  with each of the inboard  201   a  and outboard panel  201   b . The tether/lace  230  is woven through the grommets  235  traversing the air bag  201  a number of times as the tether/lace  230  extends the length of the air bag  201  emerging to the front and rear portions thereof  131 ,  132  for connection to the front and rear pillars  125 ,  126  respectively. Preferably, a pair of grommets  235  are disposed immediately adjacent one another to allow the tether/lace  230  to immediately pass back through the bottom portion of the air bag  201 . Such an arrangement limits the exposure of the tether/lace  230  and helps prevent the tether/lace  230  from rubbing against the air bag or otherwise causing kinking. 
     As can be seen in FIG. 3A the distance between the inboard panel  201   a  and outboard panel  201   b  adjacent the bottom panel is relatively small in the deflated state. Such an arrangement allows the air bag  201  and tether/lace  230  to be stored up through the front and rear pillars  125 ,  126  and roof rail  124  in a non-deployed stored state. However, when the air bag is deployed, as shown in FIG. 2B, a smaller distance spans directly between the front and rear pillars  125 ,  126 . Therefore, slack must be taken up during inflation to provide tension in the tether/lace  230  to maintain the air bag  201  in proper position. 
     Referring now to FIG. 3B, the air bag  201  is in an inflated state. Thus the distance between the grommets  235  on the inboard side of the air bag and the outboard side of the air bag is significantly greater. Thus the distance the tether/lace  230  must span is increased and slack is therefore taken up. The distance that the tether/lace  230  traverses as the air bag inflates, above that of a straight line between the connection points of the front and rear pillars  125 ,  126 , is greater than the increased distance that the tether/lace  230  must span when stored up through the front and rear pillars  125 ,  126  and across the roof rail  124 . This facilitates easy storage of the air bag  201  and tether/lace  230  in the roof rail  124  while providing ample slack take up during air bag inflation. This results in an air bag  201  that is easily folded and stored in the roof rail and having sufficient tension in the tether/lace  230  when inflated to hold and maintain the air bag  201  in a proper position. 
     A protective cover  228  may be disposed over the bottom panel  201   c  sandwiching the tether/lace  230  there between. Such an arrangement isolates the tether/lace  230  during deployment and prevents foreign objects from inhibiting the relative movement of the tether/lace  230  relative to the air bag  201  during inflation thus inhibiting kinking. 
     FIGS. 4A and 4B represent an alternate embodiment for lacing the tether/lace  330  along the air bag  301 . In this embodiment the tether/lace  330  traverses a plurality of discrete points or lace guides  335  in a serpentine fashion. The discrete points or lace guides  335  are formed by firmly stitching the bottom panel  301   c  and a protective cover  328  together at each of the lace guides/points  335 . When the air bag  301  is uninflated, the inboard and outboard sides of the bottom panel  301   c  and protective cover  328  are closer together similar to the embodiment of FIG.  3 A. Thus the length of the tether/lace  330  needed to span the air bag  301  in a deflated/stored state is shorter than when inflated. This allows the tether/lace  330  to be stored up through the pillars  125 ,  126  and along the roof rail. When the air bag  301  inflates, the inboard and outboard sides of the bottom panel  301   c  and protective cover  328  move apart and the tether lace  330  must traverse the width of the bottom panel  301   c  a number of times proportionate to the number of guides  335 . Increasing the number of guides  335  will increase the length of tether/lace  330  needed to span the air bag  301  and the amount of slack take-up during inflation. Such an arrangement eliminates the need for grommets and any exposure of the tether/lace  330  to the interior of the vehicle along the length of the air bag  301 . 
     FIGS. 5A-5C represents another embodiment of the present invention. In this embodiment, the air bag  401  comprises two panels. An inboard panel  401   a  is secured to an outboard panel  401   b  along a top edge  403  and bottom edge  404 . A plurality of tether/lace guides  435  are formed on both sides of the air bag  401   a , 401   b . The guides  435  are preferably formed of fabric looped back onto itself and stitched to the side of the air bag  401 . The fabric guide  435  is preferably made of the same material as the air bag  401 . The tether/lace  430  is simply fed through each fabric guide  435  traversing the bottom edge  404  of the air bag  401  between each successive guide  435  as illustrated in FIG.  5 C. As in the previous embodiments, when the air bag  401  is deflated, the distance between the guides  435  is small whereas when the air bag  401  is inflated, the span increases requiring a greater length of the tether/lace  435  to span the overall length of the air bag  401 . 
     Such an arrangement provides an added benefit as the tether/lace  435  may be secured to the side of the air bag without the need for a zero length tether. If a grommet or slit were used as a guide  435  and the tether/lace  430  fed there through, the integrity of the air bag would be compromised and air would escape thus defeating the utility of the air bag. To avoid such a breach, a zero length tether must be formed about the guide point should a grommet or simple slit be employed. The present embodiment eliminates the need for a zero length tether. However, the present embodiment does not exclude the use of a zero length tether and may so be employed together with the present arrangement. 
     FIGS. 6A-6C represent yet another embodiment of the present invention. As in the embodiment of FIGS. 5A-5C, a two-panel air bag  501  is employed. Inboard panel  501   a  is secured to an outboard panel  502   b  along a top edge  503  and bottom edge  504 . The two panels are simply stitched together, or as previously discussed, may be dielectrically adhered to one another in addition to the stitching. A plurality of tether/lace guides  535  are formed along the top edge  503  and bottom edge  504  of the air bag  501  in a similar fashion to the embodiment of FIG.  3 C. That is, the guides  535  are formed outside of the stitching in a waste area unexposed to the internal pressure of the inflating gas. Moreover, a plurality of fabric loop guides may be used in a similar fashion as shown in the previous embodiment. 
     The tether/lace  530  is fed through the guides  535  only along the inboard panel  501   b . Such an arrangement removes the exposure of the tether/lace  530  to the inside of the vehicle. Therefore, a pair of immediately adjacent guides  535  is formed at each point along the top and bottom edges of the air bag. Such an arrangement allows the tether/lace  530  to be immediately fed back through the edge of the air bag  501  and to be maintained on the outboard side  501   b  of the air bag. A protective cover  528  may also be employed to isolate the tether/lace  530  within the air bag  501 . 
     As illustrated in FIGS. 6A and 6B, the distance between the top edge  503  and bottom edge  504  changes between the uninflated and deflated states. L 1  represents a distance between the top and bottom edge of the air bag when inflated. However, the distance between the top edge  503  and bottom edge  504  when uninflated is significantly smaller as illustrated by reference L 2 . Of course, the air bag  501  may be folded to position the top  503  and bottom  504  edges immediately adjacent one another thereby substantially reducing the length there between. Such an arrangement increases the amount of slack take up in the tether/lace  530  when the air bag inflates from its uniflated stored state in the roof rail. 
     The material used for the tether/lace, in each of the aforementioned embodiments, may be that as is known in the art. A water based Teflon coated thick nylon tape or other strong woven fabric or cord may be employed. It is preferable that the tether/lace have no substantial independent elastic properties. That is, the tether/lace should be able to endure the desired tension without significant elongation or substantially shrinkage when tension is relieved. It is also desirable to have a strong flexible material having an external surface of relatively low frictional characteristics to facilitate easy movement relative to the air bag and guide points. It is also noted that the tether/lace may be secured to the pillars in any suitable fashion known in the art. 
     Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the present invention as defined by the appended claims.