Abstract:
An airbag cushion is disclosed for use in automotive protective systems. The airbag cushion includes a vent flap that, prior to cushion deployment, extends from the cushion exterior through a vent. A strap is coupled to the vent flap and to an interior surface of the cushion. Upon airbag deployment, the strap extends until taut or extends until the cushion encounters an obstruction. If pulled taut, the strap pulls the vent flap into the cushion interior where the interior air pressure effectively presses the vent flap against the vent. If the cushion encounters an obstruction, the strap remains lax, and the vent remains open. Means are provided for retaining the vent in the closed position during occupant ride down.

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 in which:  
         [0003]      FIG. 1A  is a side view of an embodiment of a deploying airbag cushion.  
         [0004]      FIG. 1 B  is a cross-sectional view of the airbag of  FIG. 1A .  
         [0005]      FIG. 2A  is a cross-sectional view of an embodiment of a deployed airbag.  
         [0006]      FIG. 2B  is a cross-sectional view of the airbag of  FIG. 2A .  
         [0007]      FIG. 3  is a cross-sectional view of an embodiment of an airbag after deployment.  
         [0008]      FIG. 4  is a plan view of an embodiment of a vent flap and strap.  
         [0009]      FIG. 5A  is a plan view of an embodiment of vent flap and strap.  
         [0010]      FIG. 5B  is a side view of the vent flap and strap of  FIG. 5A .  
         [0011]      FIG. 6  is a cross-sectional view of an alternative embodiment of an airbag after deployment.  
         [0012]      FIG. 7  is a cross-sectional view of an alternative embodiment of a deployed airbag.  
     
    
     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, the airbag cushion inflates and deploys through a cosmetic cover. The airbag cushion deploys towards the occupant and provides a restraint. A potentially dangerous situation occurs when an occupant is positioned too closely to the airbag which causes the occupant to contact the airbag as it is deploying. Ideally, the occupant should be in position to impact the airbag only after full deployment. It would be advantageous to provide an airbag with a softer deployment when an occupant is out-of-position. Embodiments described below provide an airbag cushion that responds to an occupant&#39;s position and vents accordingly to reduce the severity of a deploying contact. With reference now to the accompanying figures, particular embodiments of the invention will now be described in greater detail.  
         [0015]     Referring to  FIGS. 1A and 1B , views of a deployed airbag cushion  100  are shown. The airbag cushion  100  is deployed from an instrument panel  10  to restrain an occupant  12  who is “out-of-position” and is impeding airbag cushion deployment. An out-of-position occupant  12  is one who is seated in a forward position so as to obstruct the path of airbag cushion deployment. The airbag cushion  100  includes a vent  102  that allows gas to exit to enable cushion deflation. A vent flap  104  is coupled to an interior surface  106  of the cushion  100  and proximate to the vent  102 . Before deployment of the cushion  100 , the vent flap  104  partially extends out of the vent  102  and then enters back into the vent  102 . In so doing, the vent flap  104  forms a U-shape outside of the vent  102  and allows gas to exit through the vent  102 .  
         [0016]     A strap  108  couples at one end to the vent flap  104  and at an opposing end to the interior surface  106 . The strap  108  is coupled to the interior surface  106  at a location opposing a face surface  110  that contacts an occupant  12 . One or more loops  112  are coupled to the interior surface  106  and retain the strap  108  in position. The vent flap  104  and the strap  108  may be integrally formed or may be coupled to one another by stitches, bonds, or adhesives. The vent flap  104  and strap  108  may include a nylon fabric material or any other material suitable in the art.  
         [0017]     During deployment, the strap  108  is initially slack and the vent flap  104  remains partially outside of the cushion interior  114 . As the airbag cushion  100  deploys, the face surface  110  contacts the out-of-position occupant  12 . Because of the limited deployment, the strap  108  is not able to fully extend and the vent flap  104  remains extending through the vent  102 . Gas freely vents through the vent  102  and pushes against the vent flap  104  so that the vent  102  is not obscured. The airbag cushion  100  builds up less pressure and avoids injuring an occupant  12  impeding the deployment.  
         [0018]     Referring to  FIGS. 2A and 2B , views of a deployed airbag cushion  200  are shown without the occupant  12  obstructing deployment. The airbag cushion  200  is able to fully deploy before contacting the occupant  12  thereby providing maximum restraint. As the airbag cushion  200  deploys, the strap  202  is pulled until taut which forces the entire vent flap  204  into the cushion interior  206 . The vent flap  204  is pressed against the vent  208  by the interior gas pressure. The vent flap  204  is sized to extend through the vent  208 , enter the cushion interior  206 , and close against the vent  208  without exiting through the vent  208 .  
         [0019]     Referring to  FIG. 3 , a cross-sectional view of a of an airbag cushion  300  is shown after deployment and during “ride-down.” During ride-down, the airbag cushion  300  vents gas through seams or through optional unobstructed vents (not shown). The airbag cushion  300  begins to contract and the strap  302  becomes slack. The vent flap  304  is not locked into a closed position and may move due to the slack to allow further venting through the vent  306 .  
         [0020]     Referring to  FIG. 4 , a plan view of a vent flap  400  and a strap  402  is shown. The vent flap  400  couples at an end  404  to an interior surface  106  proximate to the vent  102 . Coupling may be by stitches, bond, or adhesives. The vent flap  400  includes a surface  406  sufficient to press against and cover the vent  102  without exiting through the vent  102 . The vent flap  400  may be configured to not completely cover the vent  102  when some limited venting is required. In the illustrated embodiment, the vent flap  400  includes a converging portion  408  that converges to the strap  402 . One of skill in the art will appreciate that the vent flap  400  may be configured in a variety of shapes, all of which are included within the scope of the invention.  
         [0021]     The strap  402  is depicted as a rectangular shaped member, although it may be embodied in other shapes including a cord or braid. The strap  402  couples at an end  410  to the interior surface  106  by stitches, bonds, adhesives, or the like. The strap  402  may optionally include one or more tabs  412  that are configured to pass through a loop  112  in a deployment direction, but restrict movement through the loop  112  in the opposite direction such as during ride-down. The tabs  412  may be arrayed in a “pine-tree” configuration as depicted or in other configurations known in the art.  
         [0022]     Referring to  FIGS. 5A and 5B , views of an alternative embodiment of a vent flap  500  and strap  502  are shown. The vent flap  500  includes a flap aperture  504  that is configured to allow gas venting. When in the closed position, the flap aperture  504  aligns with the vent  102  and provides limited venting. An airbag cushion would therefore have increased venting in an out-of-position condition, and limited venting in a normal seating position.  
         [0023]     The strap  502  includes a strap flap  506  that may be formed by folding over and securing a portion of the strap  502 . Alternatively, the flap  506  is formed by securing a material to the strap  502 . The flap  506  is configured to pass through a loop  112  in one direction, such as during deployment, but to catch on the loop  112  and prevent strap movement in the reverse direction. The flap  506  and loop  112  operate together to restrict movement of the strap  502  during deflation. Both the tabs  410  of  FIG. 4  or the flap  506  of  FIG. 5  may be used as a locking mechanism to retain the position of the strap  502  after airbag deployment.  
         [0024]     Referring to  FIG. 6 , a cross-sectional view of an alternative embodiment of an airbag cushion  600  is shown. The airbag cushion  600  is partially deflated after deployment which causes the strap  602  to become slack. The airbag cushion  600  is similar to that previously shown but the strap  604  includes a strap flap  606 . The strap flap  606  locks on the loop  608  during ride-down and retains the vent flap  610  in a closed position. In this manner, gas venting through the vent  612  continues to be restricted which may be desired in certain designs. As can be appreciated, the tabs  410  of  FIG. 4  may also be used as a locking mechanism to secure the strap position and retain the vent flap  610  in a closed position.  
         [0025]     Referring to  FIG. 7 , a cross-sectional view of an alternative embodiment of an airbag cushion  700  is shown. The airbag cushion  700  includes first and second vents  702 ,  704  and corresponding first and second vent flaps  706 ,  708  and first and second straps  710 ,  712 . The vent flaps  706 ,  708  and the straps  710 ,  712  are configured to operate as previously described to limit deployment impact during an out-of-position condition. The straps  710 ,  712  may be coupled at ends  714 ,  716  and proximate to one another at an interior surface  718 . The vents  702 ,  704 , vent flaps  706 ,  708 , and straps  710 ,  712  may be symmetrically disposed to provide evenly distributed venting. An airbag cushion  700  may include a plurality of vent, flap, and strap members as needed to provide the necessary conditional venting.  
         [0026]     In an alternative embodiment, a single strap may be used rather than the straps  710 ,  712 . The single strap would be secured to vent flaps  706 ,  708  and feed through one or more loops secured to an interior surface  718 . The single strap operates similar to previously described embodiments but would not be secured to the interior surface  718 .  
         [0027]     The airbag cushion  700  may further include one or more additional vents  720  to increase venting. The vents  720  provide consistent venting in that they do not depend on an occupant&#39;s position. The vents  720  may be symmetrically disposed to equalize venting distribution. The need for vents  720  is based on the airbag cushion design and the venting requirements. The vents  720  may be embodied as aperture, tubes outlets, and other shapes known in the art.  
         [0028]     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 a closed vent 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.  
         [0029]     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.  
         [0030]     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.