Abstract:
An airbag cushion is disclosed for use in automotive protective systems. The airbag cushion includes at least one closeable flap vent for re-directing gas out of the cushion when an obstruction is encountered. The airbag cushion also includes a tether for controlling the closeable flap vent.

Description:
TECHNICAL FIELD 
     The present invention relates generally to the field of automotive protective systems. More specifically, the present invention relates to inflatable airbags for automobiles. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Understanding that drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings as listed below. 
         FIG. 1A  is a perspective view of an airbag cushion partially deployed from an instrument panel towards a seat (vehicle occupant not shown). 
         FIG. 1B  is a perspective view of an airbag cushion fully deployed from an instrument panel towards a seat (vehicle occupant not shown). 
         FIG. 2A  is a perspective view of the partially deployed airbag cushion shown in  FIG. 1A  with a partial cut-away taken along cutting line  2 A- 2 A to show the open flap vent, tether and a diffuser. 
         FIG. 2B  is a perspective view of the fully deployed airbag cushion shown in  FIG. 1B  with a partial cut-away taken along cutting line  2 B- 2 B to show the closed flap vent, tether and a diffuser. 
         FIG. 3A  is a perspective view of the partially deployed airbag cushion shown in  FIG. 2A  with a partial cut-away taken along cutting line  2 A- 2 A to show the open flap vent, tether and a diffuser. While  FIG. 2A  shows the interior of the partially deployed airbag from the front to the rear,  FIG. 3A  shows the interior of the partially deployed airbag from the rear to the front. 
         FIG. 3B  is a perspective view of the partially deployed airbag cushion shown in  FIG. 2B  with a partial cut-away taken along cutting line  2 B- 2 B to show the closed flap vent, tether and a diffuser. While  FIG. 2B  shows the interior of the partially deployed airbag from the front to the rear,  FIG. 3B  shows the interior of the partially deployed airbag from the rear to the front. 
         FIG. 4A  is a perspective view of another embodiment of an airbag cushion with a partial cut-away to show the open flap vent, tether and a diffuser. 
         FIG. 4B  is a perspective view of the embodiment of the airbag cushion shown in  FIG. 4A  with a partial cut-away to show the closed flap vent, tether and a diffuser. 
         FIG. 5A  is a perspective view of the partially deployed airbag cushion shown in  FIG. 4A  which shows the interior of the partially deployed airbag from the rear to the front as opposed to the front-to-rear view provided in  FIG. 4A . 
         FIG. 5B  is a perspective view of the fully deployed airbag cushion shown in  FIG. 4B  which shows the interior of the fully deployed airbag from the rear to the front as opposed to the front-to-rear view provided in  FIG. 4B . 
         FIG. 6A  is an enlarged perspective view of another embodiment of an airbag cushion with a partial cut-away to show the flap vent, tether and the throat for entry of the inflation gas from the inflator into airbag cushion. 
         FIG. 6B  is an enlarged perspective view of the embodiment of the airbag cushion shown in  FIG. 6A  with a partial cut-away to show the closed flap vent, diffuser and the throat of the airbag cushion. 
     
    
    
     INDEX OF ELEMENTS IDENTIFIED IN THE DRAWINGS 
     
         
         
           
               40  instrument panel 
               50  seat 
               100  airbag module 
               101  airbag cushion 
               102  interior of the airbag cushion  101   
               102   f  front portion of interior  102   
               103   t  top section of front portion  102   f    
               103   b  bottom section of front portion  102   f    
               108  throat 
               110  membrane 
               111  interior surface of airbag cushion membrane 
               112  exterior surface of the airbag cushion membrane 
               113  face surface 
               116  seam 
               120  airbag module housing 
               130  diffuser 
               131  material 
               132  opening 
               133  perimeter of direct opening  134   
               134  forward opening of diffuser 
               135  side openings 
               136  perimeter of side openings  135   
               150  closeable flap vent 
               151  rim or diameter of edges of vent aperture 
               152  flap or flap section 
               153  flap attachment 
               154  flap opening 
               156  side frames of flap opening 
               158  vent aperture 
               170  control tether 
               171  tether holder 
               173  vent portion 
               174  fold 
               176  teeth 
               178  temporary holding feature 
               179  tether attachment 
           
         
       
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Described below are embodiments of an airbag cushion and venting mechanism. As those of skill in the art will appreciate, the principles of the invention may be applied to and used with a variety of airbag deployment systems including frontal driver and passenger airbags, knee airbags, overhead airbags, curtain airbags, and the like. Thus, the present invention is applicable to airbag cushions of various shapes and sizes. 
     Airbag cushions are frequently located in an instrument panel and directly in front of an occupant. During a collision, an airbag cushion inflates and deploys through a cosmetic cover. The airbag cushion deploys towards the occupant and provides a restraint. 
     Full inflation of an airbag is not always desired. For example, partial inflation offers optimal protection when the occupant being protected by the airbag cushion is a child, a baby in a rear facing car seat or an adult positioned too close to the air bag cushion. Such conditions are referred to as out-of-position conditions. Embodiments described below provide an airbag cushion that responds to an occupant&#39;s position and vents accordingly to avoid excessive deploying impact. 
     Embodiments disclosed herein permit response to occupant position and vents accordingly. Each embodiment has a closeable opening for venting gas referred to as an optionally closeable vent for out-of-position (OOP) conditions such as a flap vent or a closeable vent. Each closeable vent may be closed via a component such as a control tether. The tether may be connected at one end to a vent and at an opposing end elsewhere within or on the cushion. A diffuser may also be optionally positioned in the cushion to optimize the flow of gas out of the closeable vents. It is desirable to include a diffuser in most embodiments of the cushion due to the ability of a diffuser to enable the rapid escape of the gas out of the cushion via the closeable vents. 
     If an occupant is in close proximity to the deploying airbag and restricts normal inflation, the closeable vent remains open and allows gas to rapidly escape. If the occupant is in a normal position and inflation is unrestricted, the tension pulls on the tether to quickly close the closeable vent. Closure retains gas for normal occupant restraint. Thus, the closeable vent may be used as a variable feature in out-of-position conditions and in normal restraint conditions. In this manner, the airbag cushion is sensitive to obstructive expansion of the cushion. 
     With reference now to the accompanying figures, particular embodiments of the invention will now be described in greater detail. One embodiment of a partially deployed airbag cushion  101  is shown in various views in  FIG. 1A ,  FIG. 2A  and  FIG. 3A  with a flap vent  150  which is open and a control tether  170  which is slack. The same embodiment is shown fully inflated in  FIG. 1A ,  FIG. 2A  and  FIG. 3A  with flap vent  150  which has been closed and control tether  170  in a taut configuration. A second embodiment of flap vent  150 ′ and a control tether  170 ′ are provided in  FIGS. 4A-4B  and  FIGS. 5A-5B . The second embodiment is shown with its flap vent  150 ′ open in  FIG. 4A  and  FIG. 5A  and with its flap vent  150 ′ closed in  FIG. 4B  and  FIG. 5B . A third embodiment is shown in  FIGS. 6A-6B . The closeable flap vents are closed when the control tethers have been pulled taut due to the expansion of the cushion which is caused by the pressure of the gas in the airbag cushion. 
       FIGS. 1A-1B  show an airbag cushion  101  deploying from instrument panel  40 . To better view airbag cushion  101 , an occupant is not shown in seat  50 .  FIG. 1A  is a perspective view which shows an airbag cushion  101  as it would appear if it encountered an obstacle such as an out-of-position occupant.  FIG. 1B  is a perspective view which shows an airbag cushion  101  as it would appear without encountering an obstacle. 
       FIGS. 2A-2B  provide cut-away, perspective views of airbag cushion  101  and instrument panel  40  as shown respectively in  FIGS. 1A-1B . In addition to airbag cushion  101 , another component of airbag module  100  is also shown in  FIGS. 2A-2B , airbag module housing  120 , which is positioned under instrument panel  40 . Another component of the airbag module is an inflator (not shown) which is housed within airbag module housing  10  to inflate airbag cushion  101  with inflation gas. 
     As mentioned above, airbag cushion  101  features a flap vent  150  which is controlled via a control tether  170 . Another component is a diffuser  130 . Each of these components are described in detail below. 
     Airbag cushion  101  has an interior  102  with a front portion  102   f . As best seen in  FIG. 3B , front portion  102   f  has a top section  103   t  and a bottom section  103   b . Inflation gas passes from the inflator (not shown) and into interior  102  via a throat opening (shown only in  FIGS. 6A-6B ) in membrane  110  which is defined by a throat  108  (shown only in  FIGS. 6A-6B ). After passing through the throat opening, diffuser  130  directs the inflation gas within interior  102 . As shown in  FIG. 3B , top section  103   t  and bottom section  103   b  of front portion  102   f  significantly expands as airbag cushion  101  becomes fully deployed. 
     Membrane  110  has an interior surface  111  and exterior surface  112 . The portion of the exterior surface facing the vehicle occupant is face surface  113 . The various sections of membrane material are held together at seams  116 . Of course, membrane  110  may also be formed from a single integral material. 
     Optional diffuser  130  is configured to create a pressure pocket and re-direct the inflation gas. The embodiment of the diffuser shown in the figures at  130  is pentagon shaped and comprises a material  131  which may be integral with cushion membrane  110  or attached to cushion membrane  110 . For example, diffuser  130  may be sewn together with cushion membrane  110 . Gas enters via a diffuser opening (not shown) which corresponds with the throat opening (shown only in  FIGS. 6A-6B ). Perimeter  133  defines forward openings  134 . Forward openings  134  assist with normal inflation of cushion  100  to assist in getting cushion  100  in position in time for dynamic loading purposes. Each side opening  135  is respectively defined by a perimeter  136 . Note that while only one side of the diffuser is shown, there is a side opening opposite the side opening shown at  135 . The gas is directed out of forward openings  134  and side openings  135 . Note that in other embodiments, the optional diffuser may have other shapes and the openings may have different sizes and numbers. 
     Side openings  135  may be strategically sized, as shown in  FIG. 2B , relative to forward openings  134  to allow a greater volume to flow laterally than flows forward toward the occupant. This flow pattern enables airbag cushion  101  to inflate laterally at a quick rate while also partially inflating in a forward direction toward the occupant. In an another embodiment, the diffuser may be configured to re-direct gas at the flap vent during at least a particular stage of deployment. 
     Closeable flap vent  150  is best seen in  FIGS. 2A-2B . As shown in  FIG. 2A , the edges of membrane  110  define a vent aperture  158  and are referred to as rim  151  or diameter of the vent aperture. Vent aperture  158  in membrane  110  provides an opening for gas to exit interior  102  of airbag cushion  101  when via closeable flap vent  150  is open. Flap  152  extends within interior  102  of airbag cushion  101 . Flap  152  may be attached to cushion membrane  110  via a flap attachment  153  which in this embodiment is an anchor stitching. In another embodiment, the flap may integrally extend from the cushion membrane. Flap  152  has a configuration which enables it to close vent aperture  158  as shown in  FIG. 2B . Flap  152  may have a shape which corresponds with the shape of vent aperture  158  and be sized slightly larger than vent aperture  158 . In other embodiments, the flap may have a different shape but still be larger than the vent aperture. The flap and flap aperture may have any suitable shape such as round, elliptical, rectangular, triangular, or polygon shapes. The flap and flap aperture may have any size which enables the flap vent to close. The design permits the flap vent to be a low-stress element in the cushion assembly which is helpful during unfolding of the cushion and pressurization. The flap may comprise a nylon woven fabric-type or other suitable material known in the art. Note that the embodiments detailed herein have a single closeable vent for illustrative purposes. However, the airbag cushion  101  may include multiple vents to provide required +-venting capability. 
     Flap  152  may be connected to or integrally extend from control tether  170 . Tether  170  has a portion which rides in tether holder  171  referred to herein as a vent portion  173 . The vent portion may also include the flap and other adjacent features such as the flap attachment  153 . Vent portion  173  is shown extending from the apex of triangular flap  152 . Tether  170  is configured to move with the expansion of airbag cushion  101  to enable vent portion  173  to close closeable vent  150 . As tether  170  passes through tether holder  171 , flap  152  is lifted toward vent aperture  158 . More particularly, flap  152  is moved until the apex of flap  152  is over the apex of vent aperture  158  so that vent  150  is closed. In the embodiment depicted in  FIG. 2A , vent portion  173  has a length that is sufficient to allow vent  150  to remain in an open configuration during partial deployment. The tether may be much narrower than the flap or the width of the tether and the flap may be about the same. 
     As shown in  FIGS. 3A-3B , the end of tether  170  opposite from vent portion  173  is connected to cushion membrane  110  via a tether attachment  179 . In this embodiment, tether attachment  179  is stitching between tether  170  and cushion membrane  110 . While the depicted tether attachment serves as an anchor for an end of the tether, in another embodiment, the tether is not fixedly anchored but is moveably anchored to cushion membrane  110  via a tether attachment which is essentially a loop that permits movement of the tether. The tether attachment may be disposed elsewhere such as proximate to a different portion of interior surface  111 . Alternatively, the tether attachment may be at exterior surface  112 . For example, the tether attachment may be at the bottom of the face surface  113 , which is the surface of the airbag cushion directed to the occupant. The location of the tether attachment  179  depends on module deployment angle, vehicle interior geometry, and cushion fold type. The tether  170  may comprise a nylon material or other suitable material known in the art. Tether attachment  179  may also be located at the base of a fold and the fold may be stitched together with an optional tack stitch as disclosed in U.S. patent application Ser. No. 11/528,265 titled PRE-FOLDED AIRBAG CUSHION WITH OPTIONAL VENTING FOR OUT-OF-POSITION CONDITIONS which was filed on Sep. 27, 2006. This application is hereby incorporated by reference. 
     Note that vent  150  is in close proximity to diffuser  130  and the throat (not shown) which is the opening for the gas to enter into airbag cushion  101 . While only one vent is shown, in other embodiments two or more vents may be utilized to vent gas in a similar or identical way to vent  150 . The closeable vent(s) may be located anywhere in the cushion membrane such as the sides or bottom. A closeable vent located in the windshield side, as shown, provides ample space for venting the inflation gas. 
     As best seen In  FIG. 3A , the initially deploying airbag cushion  101  has a control tether  170  which is slack. In the initial breakout of airbag cushion  101 , closeable flap vent  150  is open. Because cushion  101  is initially in a folded condition, at initial breakout (such as the initial 7 milliseconds), closeable flap vent  150  is initially non-functional. When an occupant is not positioned directly in front of the airbag cushion  101  in  FIG. 3A , cushion  101  unfolds and is allowed to pressurize normally. If an occupant is in close proximity to airbag cushion  101  and restricts normal inflation, vent panel  150  remains open allowing inflation gas to escape. This configuration reduces the energy of the cushion and minimizes the risk of injury. 
     If an occupant is in a normal position and inflation is unrestricted, vent  150  is quickly closed as the cushion expands and gas is retained for normal occupant restraint.  FIG. 3B  provides the best view of tether  170  pulled taut so that the closeable vent  150  is closed. 
     Early in a normal inflation, gas loss through flap vent  150  is minimal even with diffuser  130 . This phenomenon is due to the Bernoulli effect—pressure is lower in a moving fluid than in a stationary fluid. For example, if the convex side of a spoon is placed into a smooth stream of water from a faucet, the spoon is pulled into the stream. The higher pressure outside the moving fluid pushes the spoon into the lower pressure water. In an airbag deployment, the high velocity stream of gas flowing into the cushion creates a similar effect for approximately 30 milliseconds, particularly in the area of the throat. Since pressure outside the cushion is still atmospheric, there is a pressure imbalance and air flows into the cushion, not out of the cushion, when the vent is positioned alongside of the gas flow stream and not in its path. This phenomenon allows the vent to be in close proximity to the inflation source, as shown. Once cushion pressure begins to increase and gas flow from the inflator starts to tail off, the flap vent needs to be closed 
     Fixed vents (not shown) which remain open may also be utilized in addition to a closeable vent to release gas. Such fixed vents provide restraint control and may be located anywhere in the cushion membrane such as in the side panels of the cushion membrane near the closeable vent. Fixed vents also provide consistent venting of airbag cushion  101  and are not restricted by an occupant&#39;s position. In addition to remaining open, fixed vents also differ from closeable vent  170  as the fixed vents are typically smaller. Fixed vents may be optional in certain cushion embodiments based on venting requirements. Like the locations for closeable vents, the location for fixed vents may vary as does the number of vents. 
       FIGS. 4A-4B  and  FIGS. 5A-5B  depict another embodiment of an airbag cushion at  101 ′. More particularly, airbag cushion  101 ′ features another embodiment of a flap vent and a tether as identified respectively at  150 ′ and  170 ′. 
     As best seen in  FIG. 5A , closeable flap vent  150 ′ has a vent aperture  158 ′ defined by a rim or diameter of edges  151 ′ which has a quadrilateral configuration. As shown in  FIG. 4A , flap opening  154 ′ is initially aligned with vent aperture  158 ′ to permit venting. When an obstruction is encountered, flap opening  154 ′ and vent aperture  158 ′ remain aligned. When there is no obstruction, airbag cushion  101 ′ fully inflates as shown in  FIG. 4B  which causes control tether  170 ′ to become taut. The movement of control tether moves flap  152 ′ into alignment with vent aperture  158 ′ to prevent venting from occurring. Flap  152 ′ has a quadrilateral configuration which is shaped like vent aperture  158 ′. Flap  152 ′ is essentially a rectangular flap section as it is an integral extension of tether  170 ′. Of course, the flap may also be attached to the tether at the vent portion. Flap attachment  153  has a configuration which securely anchors flap  152 ′ to cushion membrane  110 . As shown in  FIG. 4A , flap opening  154 ′ is defined by side frames  156 ′ on its sides and a top edge  175 ′ opposite from a bottom edge. 
     Like airbag cushion  100 , flap  152 ′ of airbag cushion  100 ′ generally matches the shape of vent aperture  158 ′ but is larger to permit a sealing effect. As the control tether  170  pulls flap vent  150  closed, loading is transmitted primarily along the outer edges of flap  152 ′ to flap attachment  153 ′. This creates a desirable perimeter tension that prevents flap  152 ′ from being forced by internal pressure out of vent aperture  158 ′. Preventing flap  152 ′ from extending out of vent aperture  158 ′ avoids a large leak from occurring. 
     Two tether holders  171 ′ are used to hold vent portion  173 ′ of control tether  170 ′. So a single tether holder may be used as shown in airbag cushion  100  or a plurality of tether holders may be used. The tether holder may also have other configurations. For example, the tether holder may be simply two slits in the cushion membrane. Tether  170 ′ further differs from tether  170  as it has a width that is the same as flap  152 . 
       FIGS. 6A-6B  provide an enlarged perspective views of another embodiment of an airbag cushion. Unlike the other embodiments, there is not a diffuser in the airbag cushion so inflation gas enters the interior of airbag cushion directly via the throat opening defined by throat  108 ″. In contrast with the embodiment depicted in  FIGS. 4A-4B  and  FIGS. 5A-5B , flap vent  150 ″ is initially closed as a segment of vent portion  173 ″ blocks venting of gas via vent aperture (not shown in  FIGS. 6A-6B ). 
     Vent portion  173 ″ has a flap  152  and a flap opening  154 ″ which are held in a fold  174 ″ by a temporary holding feature  178 . The particular temporary holding feature is a plastic fastener much like those used to hold price tags to clothing. While only a single fold is shown, other embodiments may have more than at least one fold. Temporary holding features may also be used with the other embodiments. For example, it may be useful for a temporary holding feature to be used to retain the control tether and prevent inadvertent closing of the flap vent during shipping and handling and to ensure that the tether remains slack during initial deployment of the airbag. Another example of a temporary holding feature is tack stitching which is designed to be easily broken and provides no interference to airbag cushion deployment. Other examples of releasable temporary holding features include adhesives, clips, hook and loop fasteners, knots, etc. Such releasable temporary holding features are examples of means for temporarily and releasably holding a portion of an airbag in a folded configuration. 
     Vent portion  173 ″ also has teeth  176 ″ which permit the vent portion to advance within tether holder  171 ″ and become locked. After a pair of teeth  176 ″ pass through tether holder  171 ″, it is not possible for the pair to move backwards. While a plurality of pairs are shown, a single pair of teeth could also be utilized. 
     Embodiments of vents which can be closed via a tether attached to the membrane cushion are also disclosed in U.S. patent application Ser. No. 11/528,118 titled AIRBAG CUSHION WITH A LACED VENT TO OPTIONALLY VENT GAS FOR OUT-OF-POSITION CONDITIONS which was filed on Sep. 27, 2006; U.S. patent application Ser. No. 11/296,031 titled AIRBAG CUSHION WITH DIFFUSER AND CINCH TUBE TO VENT GAS FOR OUT-OF-POSITION CONDITIONS which was filed on Dec. 7, 2005; U.S. patent application Ser. No. 11/295,953 titled LOCKING MECHANISM FOR A CINCH TUBE TO VENT GAS OF AN AIRBAG CUSHION which was filed on Dec. 7, 2005; U.S. patent application Ser. No. 10/959,256 titled AIRBAG CUSHION WITH VENT FOR REDUCED OUT-OF-POSITION EFFECTS which was filed on Oct. 6, 2004; U.S. patent application Ser. No. 10/959,387 titled AIRBAG CUSHION WITH TETHER DEACTIVATED VENTING FOR REDUCED OUT-OF-POSITION EFFECTS which was filed on Oct. 6, 2004; and U.S. patent application Ser. No. 10/832,843 titled CUSHION VENTING DESIGN FOR OUT OF POSITION OCCUPANT PROTECTION which was filed on Apr. 27, 2004. These applications are hereby incorporated by reference. 
     Various embodiments for closeable vents have been disclosed herein. The closeable flap vents disclosed herein are examples of flap vent means for selectively venting gas out of the airbag. The flaps are examples of means for covering a vent aperture in the cushion membrane to vent gas out of the airbag. A control tether, as disclosed herein, is an example of means for restricting gas venting by moving the covering means upon inflatable airbag deployment without obstruction and enabling the vent aperture to remain uncovered upon inflatable airbag deployment with obstruction. The control tether is also an example of means for restricting gas venting by closing the venting means upon inflatable airbag deployment without obstruction and enabling the venting means to remain open upon inflatable airbag deployment with obstruction. The diffusers disclosed herein are examples of means for diffusing gas within an airbag cushion by re-directing inflation gas received from an inflator. 
     Embodiments disclosed herein illustrate novel techniques for venting an airbag cushion to retain an open vent when an occupant obstructs the path of a deploying cushion and to close and remain closed when an occupant does not obstruct a deploying cushion. Airbag cushions provide improved safety by deploying with less pressure when an occupant is obstructing deployment. The airbag cushions deploy with more pressure when an occupant is not obstructing deployment and when high pressure is required to provide the necessary restraint. The airbag cushions described herein have application to both driver and passenger positions. Furthermore, the airbag cushions may be configured in a variety of sizes based on design constraints. 
     It will be apparent to those having skill in the art that changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. Embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows. Note that elements recited in means-plus-function format are intended to be construed in accordance with 35 U.S.C. § 112¶6.