Hybrid inflator

An inflator (20) comprising:

• a pressure vessel (22) made of a thin walled steel tubing (24), having a first (26) and a second (28) end, the first end closed by one of an end plate and cap (30) sealed thereto to provide a gas tight seal therebetween to inhibit inflation gas from within the pressure vessel,
• a propellant housing (50) comprising a first counter bore (52), which functions as a combustion chamber (54), a plurality of axial bores (56a-d) exiting through an adjacent part (58) of the housing (50) and intersecting a face (60) thereof, the face of the adjacent housing part including a second counter bore (70) remote from the axial bores, a plurality of radial bores (72a-d), remote from the axial bores, radially extending from the second counter bore (70) to an exit port, screen means (84), about the exit port, for filtering products of combustion produced upon use of the inflator,
• the propellant housing, at its adjacent housing part (58) including a stepped shoulder (86) fitted to the second end of the pressure vessel, a seal (87) is provided to yield a gas tight seal therebetween to inhibit escape of the inflation gas,
• a multi-function disk assembly (100) having a central portion (102) forming a rupture disk extending across the second counter bore (70) and a radially extending outer portion (104) fitted to the face (60), a circumferential seal (112) is located on the outer portion, radially outside of the rupture disk to secure the central portion to the propellant housing face (60), the outer portion also secured to the face by a second circumferential seal (114) radially outside of ends of the plurality of axial passages (56), the portion of the outer portion, of the multi-function assembly, covering the ends of the axial passages being breakable in response to the products of combustion, including pressure buildup in the chamber,
• a propellant assembly (120) received within the first counter bore (52) comprising an ignitor means (122) for generating heat upon activation, a quantity of propellant (130) ignitable in response to burning of the ignitor means, the rate of the burning of the propellant being controlled in part by the pressure within the pressure chamber (54), wherein the products of combustion in the pressure chamber are communicated through the axial passages to cause the breaking of the outer portion of the multi-function disk assembly to permit the products of combustion to enter the pressure vessel and heat the inflation gas stored therein, the rupture disk breakable in response to the buildup of pressure in the pressure vessel, wherein upon breaking of the rupture disk inflation gas flows out of the inflator through the radial passages exiting the inflator.