Air bag with adaptive tether

Abstract

An apparatus ( 10 ) for helping to protect an occupant ( 20 ) of a vehicle ( 12 ) includes an inflatable vehicle occupant protection device ( 14 ) having a deflated condition and an inflated condition. An anchor tether ( 102 ) is secured to the vehicle ( 12 ). A shaping tether ( 104 ) is secured to a first portion ( 116 ) of the protection device ( 14 ). A releasable connection ( 170 ) connects the anchor tether ( 102 ) and shaping tether ( 104 ). The shaping tether ( 104 ) secured to the vehicle ( 12 ) via the connection ( 170 ) with the anchor tether ( 102 ) restricting deployment of the first portion ( 116 ) of the protection device ( 14 ). A trigger tether ( 106 ) is secured to a second portion ( 122 ) of the protection device ( 14 ) and is configured to release the connection ( 170 ) between the anchor tether ( 102 ) and shaping tether ( 104 ) when tension in the trigger tether reaches a predetermined level. The tension in the trigger tether ( 106 ) reaches the predetermined level in response to deployment of the second portion ( 122 ) of the protection device ( 14 ) a predetermined distance.

1 . An apparatus for helping to protect an occupant of a vehicle, the apparatus comprising:
 an inflatable vehicle occupant protection device having a deflated condition and an inflated condition;   an anchor tether secured to the vehicle;   a shaping tether secured to a first portion of the protection device;   a releasable connection that connects the anchor tether and shaping tether, the shaping tether secured to the vehicle via the connection with the anchor tether restricting deployment of the first portion of the protection device; and   a trigger tether secured to a second portion of the protection device, the trigger tether being configured to release the connection between the anchor tether and shaping tether when tension in the trigger tether reaches a predetermined level,   the tension in the trigger tether reaching the predetermined level in response to deployment of the second portion of the protection device a predetermined distance.   
     
     
         2 . The apparatus recited in  claim 1 , wherein the first portion of the protection device comprises an upper portion of the protection device, and the second portion of the air bag comprises a lower portion of the protection device, the shaping tether restricting the upper portion from reaching a fully deployed condition in response to the lower portion being inhibited from reaching a fully deployed condition and thereby preventing the trigger tether from becoming tensioned to the degree necessary to release the connection. 
     
     
         3 . The apparatus recited in  claim 1 , wherein the second portion of the protection device comprises a portion of the protection device that is blocked from reaching a fully deployed condition in the presence of an occupant being positioned within a predetermined distance of the deploying protection device and preventing the trigger tether from becoming tensioned to the degree necessary to release the connection. 
     
     
         4 . The apparatus recited in  claim 3 , wherein the shaping tether restricts the upper portion from reaching a fully deployed condition in response to the lower portion being blocked from reaching the fully deployed position. 
     
     
         5 . The apparatus recited in  claim 1 , wherein the protection device comprises a frontal air bag inflatable away from an instrument panel of the vehicle to a position between the instrument panel and a front seat vehicle occupant, the first portion of the protection device comprising an upper portion of the air bag presented toward the head and upper torso of a normally seated occupant when deployed, and the second portion of the protection device comprising a lower portion of the air bag presented toward the lower torso of a normally seated occupant when deployed. 
     
     
         6 . The apparatus recited in  claim 5 , wherein the shaping tether is configured and arranged to restrict deployment of the upper portion of the air bag in response to the lower portion of the air bag being blocked from reaching a fully deployed condition. 
     
     
         7 . The apparatus recited in  claim 5 , wherein the shaping tether is configured and arranged to be released and permit unrestricted deployment of the upper portion of the air bag in response to the lower portion of the air bag reaching a fully deployed condition. 
     
     
         8 . The apparatus recited in  claim 1 , further comprising:
 an actuatable vent for venting inflation fluid from the protection device; and   a vent tether for actuating the vent, the vent tether being connected to the protection device and being operatively connected to the vent so as to actuate the vent in response to the protection device reaching a predetermined degree of deployment.   
     
     
         9 . The apparatus recited in  claim 8 , wherein the vent tether is blocked from actuating the vent in response to the connection between the shaping tether and anchor tether being maintained, the vent tether actuating the vent in response to the trigger tether releasing the connection between the shaping tether and vent tether. 
     
     
         10 . The apparatus recited in  claim 8 , wherein the vent tether is connected to the protection device at or near the location on the protection device where the shaping tether is connected to the protection device. 
     
     
         11 . The apparatus recited in  claim 8 , wherein the vent tether extends through an aperture in the anchor tether. 
     
     
         12 . The apparatus recited in  claim 8 , wherein the protection device comprises a frontal air bag inflatable away from an instrument panel of the vehicle to a position between the instrument panel and a front seat vehicle occupant, the first portion of the protection device comprising an upper portion of the air bag presented toward the head and upper torso of a normally seated occupant when deployed, and the second portion of the protection device comprising a lower portion of the air bag presented toward the lower torso of a normally seated occupant when deployed. 
     
     
         13 . The apparatus recited in  claim 12 , wherein the shaping tether is configured and arranged to restrict deployment of the upper portion of the air bag in response to the lower portion of the air bag being blocked from reaching a fully deployed condition, and wherein the vent tether is configured and arranged to leave the vent in a non-actuated condition in response to the upper portion being restricted by the shaping tether. 
     
     
         14 . The apparatus recited in  claim 12 , wherein the shaping tether is configured and arranged to be released and permit unrestricted deployment of the upper portion of the air bag in response to the lower portion of the air bag reaching a fully deployed condition, the vent tether being configured and arranged to actuate the vent in response to the unrestricted deployment of the upper portion. 
     
     
         15 . The apparatus recited in  claim 1 , wherein the protection device comprises a frontal air bag inflatable away from an instrument panel of the vehicle to a position between the instrument panel and a front seat vehicle occupant. 
     
     
         16 . The apparatus recited in  claim 15 , wherein the releasable connection comprises tear stitching,
 the tear stitching, anchor tether, and shaping tether being constructed and arranged such that tension applied to the tear stitching by the shaping tether is distributed throughout the tear stitching, the tear stitching thereby withstanding the tension applied by the shaping tether,   the tear stitching, anchor tether, and trigger tether being constructed and arranged such that tension applied to the tear stitching by the trigger tether is focused on a portion of the tear stitching, the tear stitching rupturing in response to the tension applied by the trigger tether.   
     
     
         17 . The apparatus recited in  claim 16 , wherein the tear stitching has a V-shaped configuration comprising leg portions that meet at a break point, the tear stitching, anchor tether, shaping tether, and trigger tether being constructed and arranged such that tension applied to the tear stitching by the shaping tether is distributed over the leg portions of the tear stitching, and such that tension applied to the trigger tether is focused on the break point of the tear stitching. 
     
     
         18 . The apparatus recited in  claim 1 , wherein the releasable connection comprises tear stitching, the tear stitching, anchor tether, and trigger tether being constructed and arranged such that tension on the trigger tether applied by the second portion of the protection device results in peeling forces focused initially on a predetermined portion of the tear stitching, the tear stitching rupturing in response to the peeling forces. 
     
     
         19 . The apparatus recited in  claim 1 , wherein the releasable connection comprises a knot that ties together the anchor tether, shaping tether, and trigger tether, the knot being configured such that tension on the shaping tether is transferred to the anchor tether and acts to tighten the knot, and such that tension on the trigger tether is transferred to the anchor tether and acts to loosen and untie the knot, the knot when untied releasing the shaping tether. 
     
     
         20 . The apparatus recited in  claim 1 , wherein the shaping tether and trigger tether comprise portions of a single tether, the connection connecting the single tether to the anchor tether at the interface between the shaping tether and trigger tether portions of the single tether.