Occupant restraint system for a vehicle seat including an inflatable tensioning member for an airbag

1. An occupant restraint system for a seat of a vehicle, the occupant restraint system comprising:

at least a first airbag deployable from the seat; and

at least a first tensioning member having a first portion for receiving inflation gases and a second portion attachable to the seat at a mounting location, the first tensioning member including a least a first webbing elongated between the first portion and the second portion, the first webbing at least partially constructed of a first inflatable tubular webbing adapted to receive the inflation gases for tensioning the first tensioning member at airbag deployment.

2. The occupant restraint system of claim 1 , wherein the first tensioning member further includes a second webbing extending between the first portion and the second portion.

3. The occupant restraint system of claim 2 , wherein the second webbing is at least partially constructed of a second inflatable tubular webbing.

4. The occupant restraint system of claim 2 , wherein the second webbing is a flat, non-inflatable webbing.

5. The occupant restraint system of claim 1 , wherein the first webbing is attached to the first airbag.

6. The occupant restraint system of claim 5 , wherein the first webbing is attached to an outer surface of the first airbag.

7. The occupant restraint system of claim 5 , wherein the first webbing is attached to an inner surface of the airbag.

8. The occupant restraint system of claim 1 , wherein the first webbing of the first tensioning member includes at least one manifold vent providing gas communication with the first airbag.

9. The occupant restraint system of claim 1 , wherein the first webbing includes a second portion constructed of a flat, non-inflatable webbing.

10. The occupant restraint system of claim 1 , further comprising an inflatable pelvis restraint member for extending below the seat, the inflatable pelvis restraint member in fluid communication with the first webbing of the first tensioning member.

11. The occupant restraint system of claim 1 , in combination with the seat, the first airbag carried by a seatback of the seat, the first and second portions of the first tensioning member attached to the seat.

12. A method of restraining an occupant seated on the vehicle seat with the occupant restraint system of claim 1 , the method comprising:

inflating the first webbing of the first tensioning member; and

inflating the first airbag.

13. The method of claim 12 , further comprising venting gas from the first webbing of the first tensioning member to the first airbag.

14. A vehicle seat comprising:

an inflator carried by the vehicle seat and operative to produce inflation gases;

a tensioning member having a first portion in fluid communication with the inflator and a second portion attached to the seat at a mounting location, the tensioning member including at least a first webbing elongated between the first portion and the second portion, the first webbing at least partially constructed of a first inflatable tubular webbing; and

an airbag carried by a seatback of the vehicle seat and deployable from the seat, the airbag in fluid communication with the tensioning member for delivering the inflation gases from the inflator to the airbag,

wherein the tensioning member upon inflation is operative to provide inflation gases to the airbag and position the airbag.

15. The vehicle seat of claim 14 , wherein the tensioning member includes a plurality of internal manifold vents for gas communication between first inflatable tubular webbing and airbag.

16. The vehicle seat of claim 15 , wherein the tensioning member is adapted to fill with the inflation gases before complete deployment of the airbag.

17. The vehicle seat of claim 14 , wherein the tensioning member is attached to an outer surface of the airbag.

18. The vehicle seat of claim 14 , wherein the tensioning member is attached to an inner surface of the airbag.

19. The vehicle seat of claim 14 , wherein the tensioning member has a first inflatable volume and the airbag has a second inflatable volume, the first inflatable volume being smaller than the second inflatable volume.