Airbag apparatus and tether sewing method

1. An airbag apparatus comprising:

an airbag that is folded up in a normal state and is inflated and deployed in an emergency state; and

an inflator configured to supply a deployment gas to the airbag,

wherein the airbag comprises:

a base fabric constituting an outer shell of the airbag;

a tether sewn to the base fabric and configured to restrict a shape of the airbag when the airbag is inflated and deployed by the deployment gas,

wherein

the base fabric has a first pin hole therethrough in a contact region where the base fabric and the tether contacts each other, and

the tether has a second pin hole therethrough in the contact region, wherein a position of the second pin hole corresponds to a position of the first pin hole,

wherein the tether has a folded back portion sewn to the tether and covering the first and second pin holes, and

wherein the respective first and second pin holes are configured to receive a positioning pin for fixing the base fabric and tether to each other.

2. The airbag apparatus according to claim 1 ,

wherein a sewing line of the folded back portion is formed into a loop so as to surround the first and second pin holes.

3. The airbag apparatus according to claim 1 , wherein the tether has a mark for determining a position of the folded back portion.

4. The airbag apparatus according to claim 3 ,

wherein the mark is a cut-out portion or protrusion formed along a folding line of the folded back portion, or at least one pair of cut-out portions or protrusions formed at positions that correspond to each other when the folded back portion is folded back.

5. The airbag apparatus according to claim 1 , wherein the respective first and second pin holes include a plurality of first and second in holes formed at positions serving as asymmetric triangle vertexes.

6. The airbag apparatus according to claim 1 , wherein the airbag comprises a plurality of the tethers, and arrangement of the first pin hole through the base fabric is different for each of the tethers.

7. The airbag apparatus according to claim 1 ,

wherein the tether comprises a plurality of tether portions which are separable from each other,

wherein each of the tether portions has:

a pair of protrusions at one end portion thereof; and

a pair of third pin holes provided in the pair of protrusions, and

wherein when the pair of protrusions of the adjacent tether portions overlap with each other, positions of the pair of third pin holes of the adjacent tether portions correspond to each other.

8. The airbag apparatus according to claim 1 ,

wherein the airbag further comprises:

a left inflation chamber inflated and deployed toward a left side of an occupant;

a right inflation chamber inflated and deployed toward a right side of the occupant;

a connection portion that connects the left inflation chamber and the right inflation chamber; and

a communication path which is formed in the connection portion, wherein the left inflation chamber and the right inflation chamber are communicated with each other through the communication path,

wherein the tether comprises:

a left tether, wherein one end of the left tether is sewn to a left outer panel of the left inflation chamber; and

a right tether, wherein one end of the right tether is sewn to a right outer panel of the right inflation chamber,

wherein the other end of the left tether and the other end of the right tether are connected to each other through the communication path or connected to the connection portion.

9. The airbag apparatus according to claim 8 ,

wherein each of the left and right tethers is foamed in a L-shape, and a bent portion of each of the left and right tethers is connected to the connection portion.

10. A method for sewing a tether to a base fabric of an airbag that is folded up in a normal state and is inflated and deployed in an emergency state, wherein the base fabric constitutes an outer shell of the airbag, and the tether is configured to restrict a shape of the airbag when the airbag is inflated and deployed, the method comprising:

(a) inserting a positioning pin through a first pin hole of the base fabric in a contact region where the base fabric and the tether contacts each other;

(b) inserting the positioning pin through a second pin hole of the tether in the contact region such that a position of the second pin hole corresponds to a position of the first pin hole;

(c) sewing the tether to the base fabric;

(d) removing the base fabric and tether from the positioning pin;

(e) folding back the tether so as to cover the first and second pin holes; and

(f) sewing a folded portion of the tether to the base fabric.

11. The method according to claim 10 ,

wherein in step (f), a sewing line of the folded back portion is formed into a loop so as to surround the first and second pin holes.