Knee airbag with clamshell housing

1. A knee airbag with clamshell housing module comprises:

an airbag;

an inflator;

a one-piece housing, the housing containing the airbag and inflator within a hollow interior of the housing formed by a first housing part and a second housing part, the first and second housing parts being locked together along four common sides and remain locked together in locking engagement during airbag deployment, along three common sides by a locking engagement snap in feature and where each first and second housing parts are joined by a hinge extending along a fourth housing side, the housing includes a deployable rotatable door cover formed as a portion of the second part between the hinge and a tear seam and being partially separated from the second part by the tear seam which upon deployment tears permitting the door cover to rotate and articulate about the hinge as the airbag is inflated extending upward relative to the lower portion of the instrument panel between the instrument panel and an occupant's knees.

2. The knee airbag with clamshell housing module of claim 1 wherein the hinge is near a portion of the tear seam.

3. The knee airbag with clamshell housing module of claim 2 wherein the tear seam includes three major portions extending across two opposing cover sides of the second part and across a longer cover side of the second part.

4. The knee airbag with clamshell housing module of claim 3 wherein the tear seam includes two transition portions, one transition portion extends from one of the cover sides to the hinge, the other transition portion extends from the opposite cover side to the hinge and wherein on airbag deployment the major portions tear and thereafter the transition portions tear permitting the door cover to rotate about the hinge.

5. The knee airbag with clamshell housing module of claim 1 wherein the first housing part and second housing part are snapped together along the three common sides.

6. The knee airbag with clamshell housing module of claim 5 wherein during airbag deployment the two housing parts remain locked together in a locking engagement along the three common sides and the hinge along the fourth common housing side.

7. The knee airbag with clamshell housing module of claim 6 further comprises:

a snap in feature, wherein the lower edge of each side of the first housing part includes an extending rib, each rib includes a plurality of rectangular openings, the side of the second housing part further includes a resilient extending rib extending upwardly, from each resilient extending rib are a plurality of flexible fingers, the distal end of each finger has an enlarged head, each head includes a sloping face, vertical face and inwardly extending face, which together form a hook to engage those portions of the first housing part forming the rectangular openings, as the two housing parts are joined together, the narrow tip of the head enters one of the openings, upon engagement of the sloping face, the finger moves rearward permitting the head to move through the opening, after the head is completely through the opening the resilient finger moves forward to achieve the snap-in configuration.