External and internal airbag tether arrangement

An example tethered airbag arrangement includes an airbag movable to an expanded position. The airbag includes a contact face. An internal tether constrains expansion of the contact face. An external tether also constrains expansion of the contact face.

BACKGROUND

This invention relates to constraining an airbag during deployment using an external tether and an internal tether.

Known airbag arrangements protect vehicle occupants by absorbing forces generated during collisions, for example. Many airbag arrangements are used in conjunction with other vehicle safety systems, such as seat belts. Safety systems having airbag arrangements protect occupants located in various positions within the vehicle.

Forces transfer between an occupant and an airbag when the occupant contacts the airbag during a collision, for example. Generally, it is desirable to contact the occupant with a substantially planar, vertically-orientated airbag contact face when the airbag is fully expanded, as this orientation often enhances force absorption. As known, the occupant can often more effectively absorb forces through their chest or thorax area than through their head and neck. Manipulating the airbag's orientation when the airbag contacts the occupant can affect the distribution of forces on the occupant. Manipulating the orientation of the airbag is often difficult due in part to rapid inflation of the airbag from a folded position.

SUMMARY

An example tethered airbag arrangement includes an airbag movable to an expanded position. The airbag includes a contact face. An internal tether constrains expansion of the contact face. An external tether also constrains expansion of the contact face.

Another example tethered airbag arrangement includes an airbag having a contact face. The airbag includes an upper airbag section and lower airbag section. The airbag includes an airbag contact face. An internal tether constrains expansion of the airbag contact face. An external tether constrains expansion of the upper airbag section.

Yet another example tethered airbag arrangement includes an airbag movable to an expanded position. An internal tether connects a base of the airbag and a contact face of the airbag. An external tether connects a base of the airbag and a contact face of the airbag.

These and other features of the example disclosure can be best understood from the following specification and drawings, the following of which is a brief description:

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIG. 1, an example tethered airbag arrangement10includes an airbag14, which is expandable within a vehicle18. An inflator22, represented schematically here, generates gas26for inflating the airbag14. Some of the gas26escapes through vents32in the airbag14. As known, vents32may be used to control the perceived hardness, softness, or both of the airbag14.

Referring now toFIGS. 2 and 3with continuing reference toFIG. 1, in these examples, the airbag14is shown in an expanded position or a position appropriate for absorbing force from an occupant50. During a collision for example, the airbag14expands and moves toward the occupant50as the occupant50moves toward the airbag14. Eventually, the occupant50contacts a contact face30of the airbag14. As known, the airbag14absorbs force from the occupant50.

In this example, an external tether34constrains areas of the airbag14to alter the profile of the contact face30, which affects the force absorption characteristics of the airbag14. The external tether34constrains an upper section38of the airbag14, but not a lower section42of the airbag14, in this example. Accordingly, the chest area46or thorax area of the occupant50contacts the lower section42of the airbag prior to a head54and neck of the occupant50contacting the upper section38of the airbag14, for example. Thus, the head54of the occupant50is impacted at a delayed time than the chest area46.

Stitching58secure one end of the external tether34to the airbag14. In this example, a central strap section62of the external tether34is secured to the airbag14with the stitching58. Individual tethers66of the external tether34extend away from the central strap section62and connect the central strap section62adjacent a base70of the airbag14. The base70includes a fixture (not shown) that holds the airbag14when the airbag14is folded. The external tether34is anchored near the base70using at least one bolt74near the base70.

As perhaps best shown inFIG. 1, the example external tether34causes a “W” profile in the upper section38due to the airbag14bulging around the tethers66and the central strap section62. In this example, a middle portion78of the upper section38extends vertically upward further than outer portions79of the upper section38. In this example, the middle portion78, or the portion between the individual tethers66, provides clearance for accommodating, at a minimum, the head width of a 3-6 year old.

In some examples, the external tether34is a breakable or expandable tether, in such examples, the external tether34may constrain the contact face30, the upper section38, or both as the airbag14deploys rather than only when the airbag14is fully deployed.

Referring now toFIGS. 4 and 5with continuing reference toFIG. 2, the example tethered airbag arrangement10also includes an internal tether80for restraining the contact face30. The internal tether80holds the airbag14during deployment to allow the lower section42to deploy more quickly. Deploying the lower section42in this manner facilitates expanding the contact face30in an appropriate orientation for absorbing force from the occupant50.

In this example, the internal tether80includes two individual tethers extending from the contact face30toward the base76of the airbag14. In this example, the internal tether80is formed from a single strip of material, which is folded and sewn adjacent the contact face30while the remaining ends are secured using the at least one bolt74, for example, near the base76of the airbag14.