Safety venting with passively closeabvle vents

Abstract

The airbag cushion has a passive venting system that remains open or transitions to a closed position depending on the impact of the airbag with an occupant and the position of the occupant. The venting system self closes upon deployment when an occupant is not out of position but remains open when an occupant is out of position. The venting system self closes due to cushion membrane tension.

1 . An airbag module, comprising:
 an inflatable airbag cushion comprising a cushion membrane which defines an interior of the inflatable airbag cushion;   at least one closeable vent comprising a vent opening in the cushion membrane and a vent cover that extends over the vent opening;
 wherein the vent cover has four sides, 
 wherein two of the sides are opposed to each other and are attached to the cushion membrane via stitches, and 
 wherein the other two sides include a side that is unattached to the cushion membrane and that is opposite a side that is attached to the cushion membrane via stitches; 
 wherein the vent cover is initially positioned to be distended away from the vent opening such that the vent is initially open; 
 wherein upon deployment of the inflatable airbag cushion with obstruction, the vent cover remains positioned such that the vent is open; and 
 wherein upon deployment of the inflatable airbag cushion without obstruction, the inflatable airbag cushion fully inflates such that the unattached side of the vent cover moves due to cushion membrane tension until the vent cover is taut and covers the vent opening to prevent inflation gas from exiting via the vent opening. 
   
     
     
         2 . The airbag module of  claim 1 , wherein the vent opening is slit-shaped with a curvature that is concavely bowed downward away from the unattached side of the vent cover. 
     
     
         3 . The airbag module of  claim 1 , wherein the unattached side of the vent cover has stitches extending along its length with a curvature that is concavely bowed downward toward the opposite side that is attached to the cushion membrane. 
     
     
         4 . The airbag module of  claim 3 , wherein the stitches that extend along the length of the unattached side of the vent cover extend beyond the vent cover into the cushion membrane. 
     
     
         5 . The airbag module of  claim 3 , wherein the attached side of the vent cover that is opposite the unattached side of the vent cover has stitches with a curvature that is convexly bowed upward toward the unattached side of the vent cover. 
     
     
         6 . The airbag module of  claim 1 , wherein the stitches of the two opposing sides that are attached to the cushion membrane are generally straight and parallel with respect to each other. 
     
     
         7 . The airbag module of  claim 1 , wherein the airbag cushion has a throat portion which receives inflation gas from an inflator, wherein the vent opening and vent cover are oriented downstream of the gas flow out of the throat portion at an angle that is about 90° with respect to the flow of gas out of the throat portion. 
     
     
         8 . The airbag module of  claim 1 , wherein the airbag cushion has a throat portion which receives inflation gas from an inflator, wherein the vent opening and vent cover are oriented downstream of the gas flow out of the throat portion at an angle that is less than 90° with respect to the flow of gas out of the throat portion.