# US 7,407,184 B2 · Micro gas generator including an initiator blast shield > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,184 B2 - Document ID: US7407184B2 - Status: Granted - Kind: B2 - Application number: 10/869,335 - Filed: 2004-06-15 - Published: 2005-01-27 - Granted: 2008-08-05 - Earliest claimed: 2003-06-16 - Assignees: Automotive Systems Laboratory, Inc. - Inventors: Bruce A. Stevens; Steven M. G. Dunham - Web page: https://patentgrep.com/patent/US7407184B2 ## CPC - B60R 22/4628: {characterised by fluid actuators, e.g. pyrotechnic gas generators (actuating a cable B60R22/4619)} - F42B 3/04: for producing gas under pressure {(generators of inflation fluid especially adapted for vehicle air bags B60R21/26)} - B60R 2022/4647: {the driving means being a belt, a chain or the like} - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR - F42B: EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION (explosive compositions C06B; fuzes F42C; blasting F42D) ## Abstract A micro gas generator 10 is provided primarily for supplying and directing gas from the combustion of pyrotechnic materials into a seatbelt pretensioner 26, for example. A perforated housing 12 of gas generator 10 provides a body for containment of the other gas generant constituents, and forms a propellant chamber 14. A propellant or gas generant 16 is contained within chamber 14 and provides combustion thereof. An annular bore 20 is centrally oriented within the bore seal 18 thereby providing a seat for an associated initiator 22. An initiator blast shield 36 is encased about the initiator 22 thereby attenuating or mitigating the force and progression of the combustion of an ignition compound (not shown) within the initiator 22. ## Claims ### Claim 1 A seatbelt device comprising: a seatbelt refractor comprising a spool; a seatbelt wound about said spool; and a seatbelt pretensioner comprising a gas generator, wherein said gas generator comprises a perforated housing having a first end, a second end, a circumference about said housing, and a plurality of gas exit orifices spaced circumferentially about said housing, said gas exit orifices spanning an arc less than half of said circumference to provide a directed gas flow from the housing; a propellant contained within said housing; an initiator fixed within said first end to ignite said propellant upon actuation of said pretensioner; and an initiator blast shield fixed about said initiator thereby insulating said propellant from said initiator, whereby upon activation of said pretensioner, said initiator produces pressurized combustion products within said initiator blast shield, said shield employed to modify the force of the initiator combustion products as it passes into the propellant for combustion thereof. ### Claim 2 (depends on 1) The seatbelt device of claim 1 wherein the blast shield has a plurality of portions adapted for facilitating localized passage of initiator combustion products therethrough upon activation of the initiator, to modify the force of the initiator combustion products as they pass into the propellant for combustion thereof, each of said blast shield portions corresponding to and being aligned with a respective gas exit orifice of said plurality of gas exit orifices. ### Claim 3 (depends on 1) The seatbelt device of claim 1 wherein said initiator blast shield is formed from polymer. ### Claim 4 (depends on 3) The seatbelt device of claim 3 wherein said initiator blast shield is formed from silicone. ### Claim 5 (depends on 1) The seatbelt device of claim 1 wherein said initiator blast shield is formed from rubber. ### Claim 6 (depends on 1) The seatbelt device of claim 1 wherein said initiator blast shield is formed from a metal. ### Claim 7 (depends on 6) The seatbelt device of claim 6 wherein said initiator blast shield is formed from steel, aluminum, or a metal alloy. ### Claim 8 (depends on 2) The seatbelt device of claim 2 wherein at least one portion of the plurality of portions adapted for facilitating localized passage of initiator combustion products therethrough comprises a weakened portion of the blast shield for promoting fracture thereof. ### Claim 9 (depends on 1) The seatbelt device of claim 1 wherein the plurality of portions adapted for facilitating localized passage of initiator combustion products therethrough comprise a plurality of weakened portions. ### Claim 10 A gas generator comprising: a housing having a first end, a second end, and a plurality of gas exit orifices formed therealong; at least one gas exit orifice formed in said housing; a propellant contained within said housing; an initiator fixed within said first end to ignite said propellant upon actuation of said gas generator; and an initiator blast shield fixed about said initiator thereby insulating said propellant from said initiator, the blast shield having a plurality of portions adapted for facilitating localized passage of initiator combustion products therethrough upon activation of the initiator, to modify the force of the initiator combustion products as they pass into the propellant for combustion thereof, each of said blast shield portions corresponding to and being aligned with a respective gas exit orifice of said plurality of gas exit orifices, whereby upon actuation of said gas generator, said initiator produces combustion products within said initiator blast shield. ### Claim 11 (depends on 10) The gas generator of claim 10 further comprising: a circumference about said housing; and wherein the plurality of gas exit orifices is spaced circumferentially about said housing, said gas exit orifices spanning an arc less than half of said circumference thereby providing a directed gas flow. ### Claim 12 (depends on 10) The gas generator of claim 10 wherein said initiator blast shield is formed from a polymer, a rubber, or a metal. ### Claim 13 (depends on 10) The gas generator of claim 10 wherein at least one portion of the plurality of portions adapted for facilitating localized passage of initiator combustion products therethrough comprises a weakened portion. ### Claim 14 (depends on 11) The gas generator of claim 11 wherein the plurality of portions adapted for facilitating localized passage of initiator combustion products therethrough comprise a plurality of weakened portions. ### Claim 15 (depends on 12) The gas generator of claim 12 wherein said initiator blast shield is formed from silicone. ### Claim 16 A method of tailoring an output of a gas generator comprising: providing a housing having a circumference; forming a plurality of gas exit orifices spaced circumferentially about the housing, wherein the gas exit orifices span an arc less than half of the circumference thereby providing a directed gas flow; providing a propellant contained within the housing; fixing an initiator within the housing to ignite the propellant upon actuation of the gas generator, and providing an initiator blast shield encased about at least a portion of the initiator thereby insulating the propellant from the initiator and modifying the force of the initiator combustion products as it passes through the initiator blast shield and into the propellant. ### Claim 17 (depends on 16) The method of claim 16 further comprising the step of: weakening at least one portion on the initiator blast shield to promote rupture thereof. ### Claim 18 (depends on 16) The method of claim 16 further comprising the steps of: providing a plurality of portions of the blast shield adapted for facilitating localized passage of initiator combustion products therethrough upon activation of the initiator; and aligning the plurality of portions of said blast shield in correspondence with the at least one gas exit orifice in the housing. ### Claim 19 (depends on 18) The method of claim 18 wherein the step of providing a plurality of portions of the blast shield adapted for facilitating localized passage of initiator combustion products therethrough upon activation of the initiator further comprises the step of forming a plurality of weakened portions, each weakened portion corresponding to and aligned with a respective gas exit orifice of the plurality of gas exit orifices to provide directed gas flow.