Abstract:
An airbag cushion is disclosed for use in automotive protective systems. The airbag cushion includes a diffuser tethered to the membrane of the cushion. The airbag cushion partially expands when an obstruction is encountered and fully expands when no obstruction is encountered. The tethered diffuser is controlled by expansion of the cushion. This permits the cushion to vary the amount of gas vented from the cushion to adjust for out-of-position conditions and normal restraint conditions.

Description:
TECHNICAL FIELD  
       [0001]    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 
         [0002]    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. 
           [0003]      FIG. 1A  is a cross-section view of an airbag module encountering an out-of-position vehicle occupant shown in a passenger seat of a vehicle. 
           [0004]      FIG. 1B  is a cross-section view of the embodiment of the airbag module shown in  FIG. 1A  with the airbag cushion fully expanded as the vehicle occupant is in a normal position. 
           [0005]      FIG. 2A  is a perspective view of the embodiment of the airbag cushion shown in  FIGS. 1A-1B . The airbag cushion is shown deploying upon encountering an out-of-position occupant. The airbag cushion is depicted with a partial break-away view to show the control tether in a slack condition and to show the interior of the airbag cushion. 
           [0006]      FIG. 2B  is a perspective view of the embodiment of the airbag cushion shown in  FIGS. 1A-2A  after it has fully deployed. The airbag cushion is depicted with a partial break-away view to show the control tether in a taut condition and to show the interior of the airbag cushion. 
           [0007]      FIG. 3A  is a cross-section view of another embodiment of an airbag module encountering an out-of-position vehicle occupant shown in a passenger seat of a vehicle. 
           [0008]      FIG. 3B  is a cross-section view of the embodiment of the airbag module shown in  FIG. 3A  with the airbag cushion fully expanded as the vehicle occupant is in a normal position. 
           [0009]      FIG. 4A  is a cross-sectional view of the embodiment of the airbag cushion shown in  FIGS. 3A-3B  with the diffuser and tether shown in a perspective view. The airbag cushion is shown deploying upon encountering an out-of-position occupant. The airbag cushion is depicted with a partial break-away view to show the control tether in a slack condition and to show the interior of the airbag cushion. 
           [0010]      FIG. 4B  is a perspective view of the embodiment of the airbag cushion shown in  FIGS. 3A-4A  after it has fully deployed with the diffuser and tether shown in a perspective view. The airbag cushion is depicted with a partial break-away view to show the control tether in a taut condition and to show the interior of the airbag cushion. 
           [0011]      FIG. 5A  is a perspective view of a closeable diffuser vent which is open. 
           [0012]      FIG. 5B  is a perspective view of the diffuser vent in  FIG. 5A  after cinching. 
           [0000]    
         
           
                 
               
                 
                 
               
             
                 
                     
                 
                 
                   Index of Elements Identified in the Drawings 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                    30 
                   occupant 
                 
                 
                    40 
                   instrument panel 
                 
                 
                    50 
                   seat 
                 
                 
                   100 
                   airbag module 
                 
                 
                   101 
                   airbag cushion 
                 
                 
                   102 
                   interior of the airbag cushion 101 
                 
                 
                    102f 
                   front portion of interior 102 
                 
                 
                   108 
                   throat 
                 
                 
                   110 
                   membrane 
                 
                 
                   111 
                   interior surface of airbag cushion membrane 
                 
                 
                   112 
                   exterior surface of the airbag cushion membrane 
                 
                 
                   113 
                   face surface 
                 
                 
                   120 
                   airbag module housing 
                 
                 
                   122 
                   inflator 
                 
                 
                   130 
                   diffuser 
                 
                 
                   131 
                   material 
                 
                 
                   132 
                   opening 
                 
                 
                   133 
                   perimeter of direct opening 134 
                 
                 
                   134 
                   additional fixed diffuser vents 
                 
                 
                   135 
                   diffuser vents 
                 
                 
                   136 
                   perimeter of diffuser vents 135 
                 
                 
                   138 
                   tack stitch 
                 
                 
                   139 
                   ruptured tack stitch 
                 
                 
                   141 
                   rim or diameter of diffuser tube 
                 
                 
                   142 
                   tube of diffuser vent 
                 
                 
                   143 
                   tether holder of vent such as a sleeve 
                 
                 
                   144 
                   holes in tether holder of diffuser vent 
                 
                 
                   150 
                   cushion vent 
                 
                 
                   151 
                   rim or diameter of cushion vent 
                 
                 
                   170 
                   control tether 
                 
                 
                   171 
                   tether attachment 
                 
                 
                   173 
                   vent portion of vent tether 
                 
                 
                   179 
                   tether attachment 
                 
                 
                     
                 
               
            
           
         
       
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0013]    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. 
         [0014]    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. 
         [0015]    Full inflation of an airbag is not always desired. For example, partial or suppressed inflation may offer 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. 
         [0016]    Embodiments disclosed herein permit response to occupant position and vents accordingly. Each embodiment of the airbag cushion has a first cushion vent in the cushion membrane for venting gas. Each embodiment has a diffuser to re-direct the inflation gas from the inflator elsewhere within the airbag cushion. Each diffuser has a first diffuser vent for venting gas out of the diffuser. Each diffuser is connected to the cushion membrane 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. 
         [0017]    If an occupant is in close proximity to the deploying airbag and restricts normal inflation, the diffuser vent directs gas to the cushion vent to allow gas to rapidly escape. If the occupant is in a normal position and inflation is unrestricted, the tension pulls on the tether to prevent gas from being directed at the cushion vent via the diffuser vent. Thus, the configuration permits the cushion to vary as needed for out-of-position conditions and normal restraint conditions. In this manner, the airbag cushion is sensitive to obstructive expansion of the cushion. 
         [0018]    With reference now to the accompanying figures, particular embodiments of the invention will now be described in greater detail. One embodiment of airbag module  100  is shown in  FIGS. 1A-2B  comprising an airbag cushion  101  and a housing  120 . Another embodiment of the airbag module is shown in  FIGS. 3A-4B  at  100 ′.  FIG. 1A  and  FIG. 2A  provide different views of a partially deployed airbag cushion  101  with a diffuser  130  positioned to direct inflation gas out of its diffuser vents  135   a - b  to the respective cushion vents  150   a - b  as control tether  170  is slack. The same embodiment is shown fully inflated in  FIG. 1B  and  FIG. 2B  with diffuser vents  135  misaligned with the respective cushion vents  150  as control tether  170  is in a taut configuration. Like  FIG. 1A  and  FIG. 2A ,  FIG. 3A  and  FIG. 4A  provide different views of a partially deployed airbag cushion  101 ′ with a slack control tether  170 ′. In  FIG. 3A  and  FIG. 4A , diffuser vents  135 ′ of diffuser  130 ′ remain open to direct inflation gas to the respective cushion vents  150  with which they are aligned. The same embodiment is shown fully inflated in  FIG. 3B  and  FIG. 4B  with diffuser vents  135 ′ closed and no longer aligned to block the flow of inflation gas out of the diffuser vents  135 ′ to the respective cushion vents  150  as control tether  170 ′ is in a taut configuration. 
         [0019]      FIGS. 1A-1B  respectively show an occupant  30  in an out-of-position (OOP) condition and in a normal condition.  FIG. 1A  shows occupant  30  leaning toward instrument panel  40  at the time of deployment while  FIG. 1B  shows occupant  30  seated upright in seat  50 .  FIG. 2A  show airbag cushion  101  as it would appear upon encountering an obstacle such as an out-of-position occupant.  FIG. 2B  shows airbag cushion  101  as it would appear without encountering an obstacle. 
         [0020]      FIGS. 1A-1B  show inflator  122  delivering gas into airbag cushion  101  via diffuser  130  within airbag cushion  101 . Inflator  122  is within airbag module housing  120  which is positioned under instrument panel  40 . Diffuser vent  135   b  and cushion vent  150   b  are shown in the view provided by  FIGS. 1A-1B  while diffuser vent  135   a  and cushion vent  150   a  are not shown. Diffuser vents  135   a - b  are aligned with cushion vents  150   a - b  in  FIG. 1A  and are misaligned in  FIG. 1B . The alignment is enabled by control tether  170  remaining slack while misalignment is caused by control tether  170  being pulled taut. As indicated above, control tether  170  becomes taut by expansion of the cushion due to the pressure of the gas in airbag cushion  100  when an out-of-position occupant is not encountered. 
         [0021]    Some of the structures of the airbag cushion  101  are best seen with reference to  FIGS. 2A-2B  while  FIGS. 1A-1B  identify only some components such as diffuser  130 , diffuser vent  135   b , cushion vent  150   b , and control tether  170 . Airbag cushion  101  has an interior  102  with front portion  102   f.  Airbag cushion  101  also has a membrane  110  with an interior surface  111  and exterior surface  112 . Gas enters interior  102  via an opening in the membrane  110 , throat  108 . More specifically, gas enters into the airbag from throat  108  via opening  132  of diffuser  130 . Cushion vents  150   a - b  in membrane  110  enable gas to exit interior  102  of airbag cushion  101 . Each cushion vent has a rim or diameter as identified in  FIGS. 2A-2B  at  151   a - b.    
         [0022]    Diffuser  130  is configured to create a pressure pocket and re-direct the inflation gas to the cushion vents  150   a - b . The embodiment of the diffuser shown in  FIG. 2A-2B  at  130  is pentagon shaped. In other embodiments, the diffuser may have other shapes. For example, the diffuser may be rectangular, trapezoidal, hexagonal, round, etc. It may also have a portion which is round or elliptical while other portions are angled. Diffuser  130  comprises a material  131  which may be integral with a surface of cushion  101  or attached to cushion  101 . For example, diffuser  130  may be sewn together with the cushion. 
         [0023]    Diffuser vents  135   a - b  (not shown in  FIGS. 1A-1B ) are respectively defined by perimeters  136   a - b  (not shown in  FIGS. 1A-1B ). Not only are diffuser vents  135   a - b  strategically located to redirect the gas flow generally toward cushion vents  150   a - b  and out of interior  102  but diffuser vents  135   a - b  may also be sized for optimal gas flow. In the depicted embodiment, diffuser vents  135   a - b  are large enough to allow most of the gas to flow through them. In addition to diffuser vents  135   a - 135   b , one or more additional fixed vents may also be utilized as shown in  FIGS. 4A-4B  at  134 ′. 
         [0024]    Because diffuser  130  and cushion vents  150   a - b  are independent of each other, the diffuser openings  135   a - b  can extend beyond cushion vents  150   a - b  when no obstruction is encountered, such as an out-of-position occupant. The same is true for the embodiment of the diffuser identified at  130 ′ in  FIGS. 3A-4B . 
         [0025]      FIG. 2A  depicts the configuration of airbag cushion  101  when it is only partially inflated as it has encountered an obstruction. Tether  170  is attached at its diffuser end to diffuser material  131  via a tether attachment  171  and is attached at its opposing cushion end to membrane  110  via a tether attachment  179 . As shown in  FIG. 1A and 2A , tether  170  remains slack when encountering an obstruction such as an out-of-position occupant. Because tether  170  is slack, diffuser vents  135   a - b  remain aligned with cushion vent(s)  150   a - b  for rapid venting conditions. 
         [0026]    Tack stitches  138  can optionally be used to initially secure diffuser  130  to cushion membrane  110 . The ruptured tack stitches are identified in  FIG. 1B  and  FIG. 2B  at  139 . Tack stitches  138  helps ensure that diffuser vents  135   a - b  remain aligned with cushion vent(s)  150  for rapid venting. Tack stitches  138  are designed to be weak enough to easily rupture as the cushion fully expands to enable the inflation gas to provide for normal occupant restraint. Other examples of releasable temporary holding features, such as tack stitches, which ensure that the diffuser remains in the desired position include fasteners, adhesives, clips, knots, hook and loop fasteners, etc. 
         [0027]      FIG. 2B  depicts the configuration of airbag cushion  101  when it is fully inflated. Tether  170  has been pulled taut. Due to the length of tether  170  relative to the space within the front portion  102   f  of interior  102 , the expansion of airbag cushion  101  pulls diffuser  130 . Pulling diffuser  130  misaligns the large vent(s)  135   a - b  and vents  150   a - b  so that the cushion fully expands for normal occupant restraint. 
         [0028]      FIGS. 3A-3B  depict another embodiment of an airbag module at  100 ′ comprising an airbag cushion  101 ′ and an airbag module housing  120 . Diffuser  130 ′ which is shown in more detail in  FIGS. 4A-4B  has diffuser vents  135   a ′- b ′ which are linked to tether  170 ′. In contrast to diffuser vents  135   a - b  which are fixed diffuser vents, diffuser vents  135   a ′- b ′ are closeable. 
         [0029]    As shown in  FIG. 3A , when an out-of-position occupant is encountered control tether  170 ′ remains slack so that diffuser vents  135   a  ′ (not shown in  FIGS. 3A-3B ) and  135   b  ′ remain respectively aligned with cushion vents  150   a  (not shown in  FIGS. 3A-3B ) and  150   b  for rapid venting. Optional tack stitch  138  may be used to ensure initial alignment. When an occupant is in a normal position as shown in  FIG. 3B  and an obstruction is not encountered, airbag cushion  101 ′ fully expands which pulls tether  170 ′ taut. When tether  170 ′ is pulled taut, diffuser vents  135   a ′- b ′ are closed. Also, diffuser vents  135   a ′- b ′ become misaligned with cushion vents  150   a - b.    
         [0030]      FIGS. 4A-4B  provide cross-section views of the embodiment of the airbag cushion shown in  FIGS. 3A-3B  with the diffuser and tether shown in perspective views. Tether  170 ′ is shown in a slack condition in  FIG. 4A  and in a taut condition in  FIG. 4B . 
         [0031]    Control tether  170 ′ is configured to move with the expansion of airbag cushion  101 ′. One end of tether  170 ′ is connected to tube  142   A  of diffuser vent  135   a ′ by tether attachment  171   a ′ and the other end is attached to tube  142   b  of diffuser vent  135   b ′ by tether attachment  171   b ′ (not shown). Tether  170 ′ is coupled to cushion membrane  110  via a tether attachment  179 ′ which is part of or extends from membrane  110  of airbag cushion  101 . Tether attachment  179 ′ serves as an anchor for tether  170 ′. Tether attachment  179 ′ as shown in  FIGS. 4A-4B  is essentially a loop that permits movement of tether  170 ′. 
         [0032]    In the other depicted embodiment, tether attachment  179  is anchored by stitching between cushion membrane  110  and tether  170 . Two tethers like tether  170  could also be used instead of tether  170 ′ so that each tether has one end attached to a feature which closes a diffuser vent and another end which is fixedly attached to the cushion membrane like tether  170  via tether attachment  179 . Of course, diffuser  130  could also be moved by a tether such as tether  170 ′ which is attached to diffuser  130  at two points and is anchored to cushion membrane via a feature such as tether attachment  179 ′. 
         [0033]    In the depicted embodiment, tether attachment  179 ′ is located at the front portion  102   f  of the interior  102  of the cushion membrane just below face surface  113 , which is the surface of the airbag cushion directed to the occupant. The tether attachment may be disposed elsewhere such as proximate to a different portion of interior surface  111 . For example, the tether attachment may be opposite face surface  113 . Alternatively, the tether attachment may be a portion of exterior surface  112 . Thus, tether  170  may extend through the interior  102  of the airbag cushion  101  or may be positioned exterior to the airbag cushion  101 . The location of the tether attachment depends on module deployment angle, vehicle interior geometry, and cushion type. In another embodiment, the control tether is an integral extension of either cushion membrane  110  or tube  142 . The tether may comprise a nylon material or other suitable material known in the art. 
         [0034]      FIGS. 5A-5B  depict control tether  170 ′ and the components of diffuser vent  135 ′ in more detail. Note that since the features shown may be on either side of the airbag cushion no designations such as “a” and “b” are used in  FIGS. 5A-5B . Note also, that while the depicted embodiments show two cushion vents and two corresponding diffuser vents, another embodiment may only have a single cushion vent and a single corresponding diffuser vent while other embodiments may include multiple vents to provide the desired venting capability. 
         [0035]    Tether  170 ′ has an end with a tether attachment  171 ′ which is stitching, however, attachment may also be achieved by bonds, adhesives, etc. Tether  170 ′ has a vent portion  173 ′ around the majority of the perimeter of cinch tube  142 . Vent portion  173 ′ is the portion of tether  170  which actuates closeable diffuser vent  135 ′. Vent portion  173 ′ circumvents a majority of the perimeter of cinch tube  142  within sleeve  143  in order to properly tighten and restrict the cinch vent  135 ′. Vent portion  173 ′ enters sleeve  143  via sleeve aperture  144 . As shown in  FIG. 5B , sleeve  143  is gathered together when cord  170 ′ has been pulled taut. By causing cinch tube  142 , particularly rim  141 , to collapse on itself, diffuser vent  135  is closed. In other embodiments, sleeve  143  features numerous apertures to facilitate cinching or a plurality loops or tabs may collectively act as a cord holder. Optional tack stitching may be used to retain cord  170 ′ in an initially fixed position within sleeve  143  and prevent inadvertent closing of the diffuser vent  135  during shipping and handling. Such tack stitching is designed to be easily broken and provides no interference to airbag cushion deployment. 
         [0036]    Tether attachment  179  or  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/______ titled PRE-FOLDED AIRBAG CUSHION WITH OPTIONAL VENTING FOR OUT-OF-POSITION CONDITIONS which was filed on Sep. 27, 2006. An optional tack stitch is advantageous to prevent undesired closure of diffuser vents during shipping or handling and to ensure that the tether remains slack during initial deployment of the airbag. The releasable temporary holding features discussed above as alternatives to tack stitches  138  may also be used to hold a fold so that the tether does not prematurely actuate the gas venting features. 
         [0037]    Cinch tube  142  may have any suitable shape such as rectangular, triangular, or polygon shapes. The cinch tube may be embodied with a height that is sufficient to achieve desired closure. In one embodiment, the cinch tube has height which is about half of its diameter. Selecting an appropriate height to diameter ratio permits the cinch tube to close during cinching without resistance from membrane tension. The design permits the cinch tube to be a low-stress element in the cushion assembly which is helpful during unfolding of the cushion and pressurization. The cinch tube may comprise the same material used for membrane  110  such as a nylon woven fabric-type or other suitable material known in the art. Designs for incrementally closing a cinch tube are disclosed in U.S. patent application Ser. No. 11/295,953 titled LOCKING MECHANISM FOR A CINCH TUBE OF AN AIRBAG CUSHION which was filed on Dec. 7, 2005. 
         [0038]    In addition to the closeable diffuser vents in the depicted embodiments, other configurations for closeable vents may also be used. Examples of suitable configurations for a closeable vent are also disclosed in U.S. Patent Application Ser. No. 11/______, titled AIRBAG CUSHION WITH A FLAP VENT TO OPTIONALLY VENT GAS FOR OUT-OF-POSITION CONDITIONS which was filed on Sep. 27, 2006 and U.S. patent application Ser. No. 11/______, 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. 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. 
         [0039]    Additional fixed diffuser vents  134 ′ allow alternative gas flow paths into interior  102  and do not vary in flow based on encountering an obstruction. Additional fixed diffuser vents  134 ′ may be used to provide consistent venting of the airbag cushion which are not restricted by an occupant&#39;s position. Such additional fixed diffuser vents may be smaller or larger than cushion vents  150   a - b.    
         [0040]    Embodiments disclosed herein illustrate novel techniques for venting gas when an occupant obstructs the path of 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. 
         [0041]    The embodiments of a cushion vent disclosed herein are examples of means for venting gas out of the cushion membrane. The embodiments of diffusers disclosed herein are examples of means for diffusing gas by re-directing inflation gas from an inflator to a diffuser vent. The embodiments of diffuser vents disclosed herein are examples of means for venting gas out of the diffusing means. The tether disclosed herein are examples of means for tethering the diffusing means to the cushion membrane. The temporary holding features, such as tack stitches, configured to initially secure the diffusing means to cushion membrane are examples of means for temporarily securing the diffusing means to the cushion membrane. 
         [0042]    The patent applications and the patents which issue from the above referenced applications are hereby incorporated by reference. The above description fully discloses the invention including preferred embodiments thereof. Without further elaboration, it is believed that one skilled in the art can use the preceding description to utilize the invention to its fullest extent. Therefore the examples and embodiments disclosed herein are to be construed as merely illustrative and not a limitation of the scope of the present invention in any way. 
         [0043]    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 essential characteristics and 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.