Plural stage inflator

Claim 2

A plural stage inflator for use in inflating an inflatable restraint airbag cushion, said inflator comprising: a housing defining a first chamber containing a first gas generant material and a second chamber containing a second gas generant material; and igniter device comprising a dual output squib with first and second igniter chambers containing respective first and second igniter charges the first and second igniter chambers being configured in a stacked arrangement within the housing, the first and second igniter chambers being configured in a side by side arrangement within the housing wherein the dual output squib, upon activation, selectively ignites at least one of the first and second igniter charges, with the dual output squib having: a) a first stage discharge whereby the first igniter charge is ignited to produce combustion products which in turn pass to the first chamber to ignite the first gas generant material to produce inflation gas at a first output level and b) a second stage discharge whereby the second igniter charge is ignited to produce combustion products which in turn pass to the second chamber to ignite the second gas generant material to produce inflation gas at a second output level.

Claim 3

The inflator of claim 1 shaped and sized for driver side placement within a vehicle at the vehicle steering wheel.

Claim 4

The inflator of claim 1 wherein said housing also defines a central chamber wherein said igniter device is housed.

Claim 5

The inflator of claim 3 wherein at least one of said first and second chambers is in the form of annular-shaped chamber about said central chamber.

Claim 6

The inflator of claim 4 wherein each of said first and second chambers are in the form of annular-shaped chambers about said central chamber.

Claim 7

The inflator of claim 1 wherein said housing is a generally circular cylinder comprising a top wall, a bottom wall, and a generally cylindrical sidewall.

Claim 8

The inflator of claim 6 wherein the generally cylindrical sidewall includes a plurality of inflation gas exhaust openings from the first and second chambers, respectively.

Claim 9

The inflator of claim 7 wherein at least one of the gas exhaust openings from the first chamber also serves as a gas exhaust opening from the second chamber.

Claim 10

An inflatable restraint system subassembly comprising: said plural stage inflator of claim 3 wherein said housing further comprises a peripheral bracket extending radially outwardly from the cylindrical sidewall below the gas exhaust openings.

Claim 11

An inflatable restraint system comprising the subassembly of claim 9 and additionally comprising: a filter material surrounding the housing sidewall to cover at least the plurality of gas exhaust openings; an inflatable airbag cushion having an open mouth for receiving generated gas, the open mouth sized to receive the housing sidewall and the filter material, with a marginal edge of said airbag cushion defining the open mouth received adjacent the bracket; an annular airbag cushion retainer including at least an inner boundary and a body, with the inner boundary sized to receive the housing sidewall and the body sized to receive said filter material.

Claim 12

The inflator of claim 1 wherein gas generant materials of the same composition are contained in said first and second chambers.

Claim 13

The inflator of claim 1 wherein the first gas generant material contained in said first chamber differs in composition from the second gas generant material contained in said second chamber.

Claim 14

An inflatable restraint system comprising: an inflator assembly including a generally circular cylindrical housing, the housing having a top wall, a bottom wall, a generally cylindrical sidewall including a plurality of gas exhaust openings, and a peripheral bracket extending radially outwardly from the cylindrical sidewall below the plurality of gas exhaust openings, the housing defining a first chamber containing a first gas generant material and a second chamber containing a second gas generant material, said inflator assembly also including a single component igniter device comprising a dual output squib with first and second igniter chambers containing respective first and second igniter charges, the first and second igniter chambers being configured in a side by side arrangement within the housing wherein the dual output squib, upon activation, selectively ignites at least one of the first and second igniter charges the first and second igniter chambers being configured in a stacked arrangement within the housing, with the dual output squib having: a) a first stage discharge whereby the first igniter charge is ignited to produce combustion products which in turn pass to the first chamber to ignite the first gas generant material to produce inflation gas at a first output level and b) a second stage discharge whereby the second igniter charge is ignited to produce combustion products which in turn pass to the second chamber to ignite the second gas generant material to produce inflation gas at a second output level; a filter material surrounding the housing sidewall to cover at least the plurality of gas exhaust openings; an inflatable airbag cushion having an open mouth for receiving generated gas, the open mouth sized to receive the housing sidewall and the filter material, with a marginal edge of said airbag cushion defining the open mouth received adjacent the bracket; an annular airbag cushion retainer having an inner boundary, a body and an outer boundary, with the inner boundary sized to receive the housing sidewall and the body sized to receive said filter material.

Claim 15

An inflatable restraint system comprising: an inflator assembly including a generally circular cylindrical housing, the housing having a top wall, a bottom wall, a generally cylindrical sidewall including a plurality of gas exhaust openings, and a peripheral bracket extending radially outwardly from the cylindrical sidewall below the plurality of gas exhaust openings, the housing defining a first chamber containing a first gas generant material and a second chamber containing a second gas generant material, said inflator assembly also including a single component igniter device comprising a dual output squib with first and second igniter chambers containing respective first and second igniter charges, the first and second igniter chambers being configured in a side by side arrangement within the housing wherein the dual output squib, upon activation, selectively ignites at least one of the first and second igniter charges the first and second igniter chambers being configured in a stacked arrangement within the housing, with the dual output squib having: a) a first stage discharge whereby the first igniter charge is ignited to produce combustion products which in turn pass to the first chamber to ignite the first gas generant material to produce inflation gas at a first output level and b) a second stage discharge whereby the second igniter charge is ignited to produce combustion products which in turn pass to the second chamber to ignite the second gas generant material to produce inflation gas at a second output level; a filter material surrounding the housing sidewall to cover at least the plurality of gas exhaust openings; an inflatable airbag cushion having an open mouth for receiving generated gas, the open mouth sized to receive the housing sidewall and the filter material, with a marginal edge of said airbag cushion defining the open mouth received adjacent the bracket; an annular airbag cushion retainer having an inner boundary, a body and an outer boundary, with the inner boundary sized to receive the housing sidewall and the body sized to receive said filter material.

Claim 16

The inflatable restraint system of claim 13 wherein said inflator assembly housing also defines a central chamber wherein said igniter device is housed.

Claim 17

The inflatable restraint system of claim 14 wherein at least one of said first and second chambers is in the form of annular-shaped chamber about said central chamber.

Claim 18

The inflatable restraint system of claim 15 wherein each of said first and second chambers are in the form of annular-shaped chambers about said central chamber.

Claim 21

The method of claim 17 wherein both the first and second igniter charges of the dual output squib are actuated.

Claim 22

The method of claim 18 wherein the first and second igniter charges are actuated substantially simultaneously.

Claim 23

The method of claim 18 wherein the second igniter charge is only actuated at a selected time interval subsequent to actuation of the first igniter charge.