Curtain air bag assembly

1. An air bag assembly ( 10 ) comprising:

an inflator ( 40 ) for providing a source of inflation gas, and an air bag ( 20 , 20 a , 20 b ) having a first end and a second end ( 50 c , 50 d ) and a first face or side ( 28 b ) and a second face or side ( 28 a ), the air bag configured to have a first inflatable chamber ( 32 ) proximate the first end, a second inflatable chamber ( 34 ) proximate the second and a non-inflatable region ( 36 ) therebetween; the air bag including an inlet ( 38 ) communicating with the inflator ( 40 ), the air bag further including a plurality of joints or seams ( 58 ) which connect selective regions of the first and second faces ( 28 a , 28 b ) together thereby controlling the inflatable volume of the air bag, a top portion ( 55 ) of each of the plurality of joints or seams located a determinable distance from a top ( 50 ) of the air bag to form within the air bag an integral gas flow path or channel ( 120 ), the inlet ( 38 ) generally positioned spaced from the top of the air bag ( 50 ) and generally located between the first inflatable chamber and second inflatable chamber;

the air bag further including a diffuser formed of a flexible material including woven cloth, the diffuser including two opposing sides or panels of material each having a curved forward end, a curved rearward end and a curved lower portion below the forward and rearward ends; the forward end of each panel proximate the lower portion includes a first matching cut-out profile, the rearward end of each panel proximate the lower portion includes a second matching cut-out profile, a first edge seam joins the forward ends of each panel together, the panels in the vicinity of the first matching cut-out profiles are not joined together, a second edge seam joins the rearward ends of each panel together, the panels in the vicinity of the second matching cut-out profiles are not joined together, a third edge seam joining the lower portions of the panels together, the first and second matching profiles being above the third edge seam, the second edge seam forming a neck of the diffuser to receive gas, the joined forward ends facing one end of the air bag, the joined rearward ends facing the other end of the air bag;

wherein the first inflatable chamber is divided into three compartments, a first or larger volume compartment including a first opening to the gas flow path along a top of the first compartment, a second compartment smaller than the first compartment, positioned in front of the first compartment and including a second opening to the gas flow path along the top of the second compartment, the second opening being smaller than the first opening to retard gas flow to the second compartment and encourage gas flow to the first compartment, and a third compartment, being closed along a top thereof, positioned forward of the second compartment and rearward of the first end, the third compartment being open along a bottom region of the third compartment so that gas filling the third compartment must flow along a circuitous path through at least the second compartment prior to entering the third compartment.

2. The assembly according to claim 1 wherein bottom regions of the first and the second compartments are open.