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

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 in which: 
         FIG. 1A  is a side view of one embodiment of a deploying airbag. 
         FIG. 1B  is a cross-sectional view of the airbag of  FIG. 1A  taken along A-A. 
         FIG. 2A  is a side view of one embodiment of a deploying airbag. 
         FIG. 2B  is a cross-sectional view of the airbag of  FIG. 2A  taken along B-B. 
         FIG. 3  is a perspective view of an embodiment of a vent. 
         FIG. 4  is a cross-sectional view of an alternative embodiment of a deploying airbag. 
         FIG. 5A  is a cross-sectional view of an alternative embodiment of a deploying airbag. 
         FIG. 5B  is an enlarged perspective view of the alternative embodiment of a deploying airbag shown in  FIG. 5A . 
         FIG. 6  is a cross-sectional view of an alternative embodiment of a deploying airbag. 
     
    
    
     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, 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.  FIG. 1A  depicts a cross sectional view of an airbag cushion  100  deploying from a housing  10 . The airbag cushion  100  is shown colliding with an occupant  12  who is impeding the path of the deploying airbag cushion  100 . The airbag cushion  100  includes a vent  102  that is disposed on the exterior surface  103  of the cushion  100 . The vent  102  may be embodied with two flaps  104 ,  106  that are coupled to one another along their edges to form a trunk-like shape, envelope, or reed valve through which gas may pass. The flaps  104 ,  106  are coupled to the exterior surface  103  of the airbag cushion  100  so as to circumvent an aperture  110 . Coupling of the airbag flaps  104 ,  106  may be through stitches, bonding, adhesives, and the like. Alternatively, the vent  102  may include a single flap that circumvents the aperture and is coupled to itself to form an envelope through which gas may pass. 
     Referring to  FIG. 1B , and with continued reference to  FIG. 1A , a cross-sectional view of  FIG. 1A  taken along  1 B- 1 B is shown.  FIG. 1B  illustrates a first flap  104  that is coupled to the second flap  106  along edges  112 ,  114 . The airbag cushion  100  includes a tether  116  that is coupled at a proximate end  118  to either the first or second flap  104 ,  106 . The tether  116  may be integrally formed with a flap  104 ,  106  or may be coupled to a flap  104 ,  106  through stitches, bonds, adhesives and the like. A distal end  120  of the tether  116  is coupled to a distal interior surface  122  of the airbag cushion  100 . 
     The tether  116  is attached at both ends  118 ,  120  and sized appropriately so that the tether  116  pulls tight during deployment if the airbag cushion  100  deploys unimpeded. However, the tether  116  remains slack if the deploying airbag cushion  100  is impeded by an occupant  12  in its path.  FIGS. 1A and 1B  depict 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 cushion deployment. Before deployment of the airbag cushion  100 , the vent  102  is disposed outside the cushion interior  124 . During deployment, the tether  116  remains slack and the vent  102  remains outside of the cushion interior  124 . The pressure within the cushion interior  124  pushes the flaps  104 ,  106  apart, allowing gas to freely vent. In this manner, the airbag cushion  100  builds up less pressure and avoids injuring an occupant impeding the deployment. 
     Referring to  FIG. 2A  and  FIG. 2B , which is a cross-sectional view taken along  2 B- 2 B, an unobstructed deploying airbag cushion  100  is shown. The occupant  12  is positioned rearward of the deployment path. When the airbag cushion  100  deploys without being impeded, the tether  116  becomes taut and thereafter pulls the vent  102  to a position within the cushion interior  124 . With the vent  102  in the interior  124 , the interior pressure acts to push the flaps  104 ,  106  together. This effectively closes the vent  102  and prevents gas from venting. This allows the airbag cushion  100  to achieve its full pressure that will adequately protect a properly positioned occupant  12 . 
     Although a single vent  102  and aperture  110  are illustrated in embodiments herein, an airbag cushion  100  may be embodied with multiple vents  102  and apertures  110  to increase venting capability. The size of the vent  102  and aperture  110  may also be modified to provide the desired venting. 
     Referring to  FIG. 3  a perspective view of an alternative embodiment of a vent  300  is shown. Hook and loop fastener materials, such as Velcro materials, identified at  302 ,  304 , are disposed on flaps  104 ,  106  such that when the vent  102  is outside of the interior  124 , hook and loop fastener materials  302 ,  304  do not engage one another. When the vent  300  is pulled within the interior  124 , the hook and loop fastener materials  302 ,  304  engage each other as the flaps  104 ,  106  come together. The engaged hook and loop fastener materials  302 ,  304  effectively secure the flaps  104 ,  106  together. The hook and loop fastener materials  302 ,  304  and the interior pressure act together to ensure that the flaps  104 ,  106  remain secured to prevent venting even during ride down when the tether may slacken. 
     Referring to  FIG. 4 , a cross-sectional view of an alternative embodiment of an airbag cushion  400  is shown. The airbag cushion  400  is depicted as being fully deployed and the occupant  12  is in a non-obstructive position. The airbag cushion  400  is shown with an unrestrained deployment and with a taut tether  116 . The airbag cushion  400  is similar to that of airbag cushion  100  but also includes an interior loop  402 . The loop  402  may include a fabric-like material that is folded over and coupled to itself. The loop  402  is open on opposing ends with the tether  116  passing through. The loop  402  is coupled to an interior surface  404  of the airbag cushion  400  by stitches, bonds, adhesives and the like. The loop  402  controls the tether movement and provides a frictional restriction to prevent the vent  102  from exiting out of the cushion interior  124  even if the tether  116  subsequently becomes slack again. The amount of restriction provided by the loop  402  may vary depending on the longitudinal length and material of the loop  402 . 
     Referring to  FIG. 5A , a cross-sectional view of an alternative embodiment of an airbag cushion  500  is shown. The airbag cushion  500  is shown deflating after full deployment which causes the tether  116  to become slack. Deflation may occur by gas leaking through seams or venting apertures (not shown) disposed within the airbag cushion  500 . The airbag cushion  500  is similar to that of  FIG. 4 , but also includes a tether flap  502  coupled to the tether  116 . The tether flap  502  may be formed by folding over a portion of the tether  116  and securing the extending portion. Alternatively, the tether flap  502  may be formed by securing a material to the tether  116 . The tether flap  502  is configured to easily pass through the loop  402  in one direction, such as during deployment, but to catch on the loop  402  and prevent tether movement in the reverse direction. The tether flap  502  and loop  402  operate together to restrict movement of the tether  116  during deflation. The vent  102 , once entering the cushion interior  124 , is retained within the interior  124  during deflation and the flaps  104  remain secured together.  FIG. 5B  is a better view of tether flap  502 . 
     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 full deployment which causes the tether  116  to become slack. The airbag cushion  600  is similar to that of  FIGS. 1 and 2  but also includes a ring member  602  that is secured to the airbag cushion  600  within the interior  124 . The ring member  602  may be formed of a rigid material and defines a ring aperture  604  through which the tether  116  passes. The tether  116  includes a stop  606  that may be embodied in a variety of suitable shapes known in the art. 
     During airbag cushion deployment, the stop  606  passes from a position proximate to the vent  102  and through the ring aperture  604 . The stop  606  is configured to prevent passage through the ring aperture  604  for non-deploying forces. The stop  606  may be larger than the ring aperture  604  and the ring member  602  and/or stop  606  may include elastic materials to allow deformation under force. With less than deploying force, the stop  606  is unable to pass through the ring aperture  604 . Thus, during airbag cushion  600  deflation, the tether  116 , stop  606 , and ring member  602  retain the vent  102  within the airbag cushion interior  124 . 
     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. 
     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. 
     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.