Concentrically disposed airbag system for seatbelts

1. Field of the Invention An airbag system for seatbelts including a housing and an elongated one-piece tubular inflatable structure disposed within the housing, where the housing and inflatable structure include a seatbelt passageway so that a seatbelt may pass therethrough unhindered and unaffected during normal seatbelt use, while the inflatable structure remains in an uninflated state. In a collision event, an inflator causes the inflatable structure to unfold, or preferably unroll, and extend from the housing along the seatbelt, so that the inflatable structure surrounds the seatbelt over an extended length thereof to provide a cushion between the seatbelt and an occupant. Such an arrangement may be easily applied to existing seatbelt systems.