Vehicle seat assembly with air bag seam rupturing means

In a vehicle seat assembly having a seat pad associated with a frame, a trim cover extending over the seat pad and including a release seam, an air bag assembly at least partially within the trim cover, the air bag assembly being provided with a container and a lid, the container being secured to the frame so that the air bag assembly lies in a spaced relationship with the air bag release seam, the air bag assembly housing an inflator and a folded air bag that is inflated by the inflator to unfold and project outwardly from the seat through the air bag release seam when the air bag seam is in an opened position:

• a tear strap extending between the frame and the release seam, the tear strap passing around a first side of the air bag assembly;
• a guide member through which the tear strap may slidingly pass;
• and
• a tether secured between the frame and the guide member so that movement of the guide member is constrained thereby, the tether passing around a second side of the air bag assembly in relation to the side that engages the tear strap,
• the tear strap being movable in response to inflation of the air bag with sufficient force to lacerate the release seam, thereby allowing the seam to open and allow the air bag to pass therethrough,
• a method for deploying the air bag, comprising the steps of:
• inflating the air bag;
• tensioning the tear strap by outwardly directed forces of air bag deployment acting upon the tether;
• and
• lacerating the release seam by a sharp, inwardly directed tug exerted upon the release seam by tensioning forces applied to the tear strap by outward movement of the air bag in combination with the tether and the guide member.

A vehicle seat assembly comprising a frame, a seat pad associated with the frame, a trim cover extending at least partially over the seat pad and including a first and a second end portion forming a release seam, a brace extending between the first and second portions of the trim cover at the release seam to maintain the release seam in a closed position before air bag deployment, an air bag assembly at least partially within the trim cover, the air bag assembly being in a spaced relationship from the air bag release seam, the air bag assembly housing an inflator and an air bag that is inflated by the inflator to unfold and project outwardly from the seat through the air bag release seam when the air bag seam is in an opened position:

• a tear strap with a first stationary end portion and a second end portion secured to the release seam, the tear strap passing at least partially along at least a part of a first side of the air bag assembly between the air bag assembly and the frame;
• a guide member through which the tear strap may slidingly pass;
• and
• a tether having a first stationary end and a second end that engages the guide member so that movement of the guide member is constrained thereby, the tether passing at least partially around another side of the air bag assembly,
• the tear strap being movable in response to inflation of the air bag with sufficient force to rupture the release seam, thereby allowing the tear seam to open and allow the air bag to pass therethrough,
• the tear strap passing around a side of the air bag assembly that is juxtaposed with the frame.