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`US005290060A
`0
`5,290,060
`[11] Patent Number:
`[19]
`United States Patent
`
`Smith
`5
`[45] Date of Patent:
`Mar. 1, 1994
`
`[54] HYBRID GAS GENERATOR FOR AIR BAG
`INFLATABLE RESTRAINT SYSTEMS
`
`5,076,607 12/1991 Woods et al.
`5,131,680
`7/1992 Coultas et al.
`
`....................... 280/737
`...................... 280/737
`
`[75]
`
`Inventor: Bradley W. Smith, Ogden, Utah
`
`FOREIGN PATENT DOCUMENTS
`
`[73] Assignee: Morton Intgfngfiongl, Inc,’ Chicago,
`Ill.
`
`[21] Appl. No.: 989,854
`
`2330194 6/1973 Fed. Rep. of Germany ...... 280/740
`.
`Primary Exami'ner—Kar1n L. Tyson
`Attorney, Agent, or Firm—Gerald K. White
`
`[22] Filed:
`
`Dec. 14, 1992
`
`[57]
`
`ABSTRACI‘
`
`A gas generator includes a chamber in which inert gas
`under high pressure is stored, a diffuser chamber, and a
`h
`be
`.
`.
`h . h
`.
`.
`.
`'
`,‘,‘,‘;,,,,°‘;‘,‘,‘;‘
`igniting the pyrotechnic charge. As pressure in the
`combustion chamber of the pyrotechnic heater rises and
`exceeds the storage chamber pressure, a plug in a shoul-
`deg covering the pyrotechrgc nozflela or;f1'ice is unseated,
`su sequent y rupturing a t in ‘nc
`Se
`ins diaphragm
`since the latter is unsupported for a pressure differential
`in this direction. Hot gas and particles from the burning
`PYr°t°°hr“° hear the 5‘°r°d 835 031151118 3 raprd Pressure
`rise in the storage chamber. When the storage chamber
`pressure exceeds the structural capability of a thin metal
`disc between the diffuser and storage chambers, it rup-
`tures allowing the heated gas to vent through the dif-
`f
`T
`.
`h
`. b
`"5" °“ ‘‘’°5 ““°‘ 8 3“ ‘*3 assembly‘
`
`14 Claims, 6 Drawing Sheets
`
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`
`Page
`
`1of12
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`KSS 1029
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`[51]
`Int. Cl.5 ............................................ .. B60R 21/26
`[52] U.S. Cl. ........................................ 280/737%32;
`[58] Field of Search ............... 280/728, 737, 741, 740;
`222/3? 422/164» 165s 1565 137/683
`Refgrences cited
`US‘ PATENT DOCUMENTS
`3 232 481
`2/1966 Hebcnmeit
`........................... ..
`9
`9
`Berryman
`
`9/1973 Lewis et a1_ _
`3,756,621
`3,853,332 i2/1974 Lynch ................................. 422/166
`3,877,721
`4/1975 Brown, Jr.
`_
`4,095,624
`6/1978 Davis .................................... 141/18
`$2’/[93] Adams 3‘ 31-
`422/156
`/ 98
`Ad_‘““5 '3‘ 31'
`230/741
`’
`'
`. .. ... .. .
`5/1991 Faigle et al.
`. .. . . .. 280/741
`5,016,914
`5,022,674 6/1991 Frantom et al.
`280/741
`5,031,932
`7/1991 Frantom et al. .............. .. 280/741
`5,033,772 7/1991 Frantom et al.
`.................. .. 280/737
`
`222/3
`
`
`
`[56]
`
`Page 1 of 12
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`U.S. Patent
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`Mar. 1, 1994
`
`Sheet 1 of 5
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`5,290,060
`
`
`
`FIG. 3
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`
`Page 2 of 12
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`U.S. Patent
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`Mar. 1, 1994
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`Sheet 2 of 6
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`5,290,060
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`U.S. Patent
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`Mar.‘ 1, 1994
`
`Sheet 3 of 6
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`5,290,060
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`

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`U.S. Patent
`
`Mar. 1, 1994
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`Sheet 4 of 6
`
`5,290,060
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`
`Page 5 of 12
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`U.S. Patent
`
`Mar. 1, 1994
`
`Sheet 5 of 6
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`5,290,060
`
`
`
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`Page 6 of 12
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`U.S. Patent
`
`Mar. 1, 1994
`
`Sheet 6 of 6
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`5,290,060
`
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`Page 7 of 12
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`1
`
`5,290,060
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`HYBRID GAS GENERATOR FOR AIR BAG
`INFLATABLE RESTRAINT SYSTEMS
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`This invention relates to an inflator for an air bag, and
`more particularly, to the type of inflator known as a
`hybrid inflator.
`2. The Related Art
`Many types of inflators have been disclosed in the art
`for inflating an air bag for use in an inflatable restraint
`system. One involves the utilization of a quantity of
`stored compressed gas which is selectively released to
`inflate the air bag. Another derives a gas source from a
`combustible gas generating material which, upon igni-
`tion, generates a quantity of gas sufficient to inflate the
`air bag. In a third type, the air bag inflating gas results
`from a combination of stored compressed gas and a gas
`generating material. The last mentioned type is com-
`monly referred to as an augmented gas or hybrid infla-
`tor.
`a
`
`5
`
`10
`
`I5
`
`20
`
`Hybrid inflators that have been proposed heretofore
`are subject to certain disadvantages. They require glass- -
`25
`to-metal-seals or other complex sealing methods to
`maintain the high pressure seal and/or require an actua-
`tion means (mechanical or pyrotechnic) to open the
`flow passages to the air bag. Many hybrid inflator ar-
`rangements dispense cold inflating gas followed by
`heated gas. This is a disadvantage for an air bag driver
`system. Additionally, end diffusers typically used‘on'
`hybrid inflators make packaging in modules difficult.
`Thus, there is a need and a demand for improvement
`in hybrid inflators to the end of overcoming the forego-
`ing disadvantages. The present invention was devised to
`fill the gap that has existed in the art in these respects.
`SUMMARY OF THE INVENTION
`
`35
`
`30
`
`An object of the invention is to provide a hybrid
`inflator that does not require glass-to-metal-seals or
`other complex sealing methods to maintain the high
`pressure seal.
`Another object of the invention is to provide a hybrid
`inflator that does not require an actuation means (me-
`chanical or pyrotechnic) to open the passages for the
`flow of inflation gas to the air bag.
`A further object of the invention is to provide an air
`bag inflator which dispenses, in its entirety, heated gas
`to the air bag.
`Still another object of the invention is to provide for
`use with such an improved hybrid inflator a centrally
`located diffuser that provides for easier packaging in
`modules compared to end diffusers that typically are
`used in hybrid inflators.
`In accomplishing these and other objectives of the
`invention, there is provided a hybrid gas inflator includ-
`ing an enlongated generally cylindrical storage cham-
`ber for storing an inert gas under high pressure, for
`example, Argon or Nitrogen, at 2000 to 4000 pounds
`per square inch (psi). The hybrid gas inflator also in-
`cludes a pyrotechnic heater having a combustion cham-
`ber which utilizes a granular mixture of Boron Potas-
`sium Nitrate (BKNO3) or another suitable pyrotechnic
`material to heat the stored gas. A thin metal diaphragm,
`hereinafter termed a second diaphragm, is utilized to
`provide a pressure seal between the storage chamber
`and a diffuser for the inflator. The diffuser contains a
`plurality of gas orifices for dispensing gas uniformly
`
`40
`
`45
`
`S0
`
`55
`
`65
`
`2
`into the air bag assembly. The gas storage chamber is
`sealed also from the combustion chamber of the pyro-
`technic heater by a thin metal diaphragm hereinafter
`termed a “first diaphragm.” This diaphragm is welded
`around the perimeter thereof to an end of the pyrotech-
`nic heater housing and is backed up with a solid metal
`plug. The plug seats in an adjacent shoulder covering
`the nozzle orifice of the combustion chamber thereby
`providing support for the thin diaphragm across the
`entire surface thereof. This enables the diaphragm to
`withstand the loads of the high pressure gas being
`stored in the storage chamber.
`The hybrid gas generator functions, as follows. Upon
`receiving a control signal, an initiator in the pyrotech-
`nic heater
`fires,
`igniting the pyrotechnic charge
`(BKNO3). As the pressure in the combustion chamber
`rises and exceeds the high pressure of the stored inert
`gas in the storage chamber, the plug is unseated. Subse-
`quently, the first thin diaphragm ruptures‘ since it is
`unsupported when the combustion pressure of the pyro-
`technic heater exceeds the inert gas storage pressure.
`Hot gas and particles from the burning pyrotechnic
`material heat the stored gas causing a rapid pressure rise
`in the storage chamber. When -the pressure in the stor-
`age chamber exceeds the structural capability of the
`second thin metal diaphragm in the diffuser, rupture
`thereof occur. This allows the heated gas to vent
`through the diffuser orifices into the air bag assembly.
`Located between the diffuser diaphragm and the stor-
`age chamber are one or more constricting orifices
`which throttle the flow of gas from the storage chamber
`and provide for the proper fill rate to the air bag assem-
`bly.
`The various features of novelty which characterize
`the invention are pointed out with particularity in the
`claims annexed to and forming a part of this specifica-
`tion. For a better understanding of the invention, its
`operating advantages, and specific objects attained by
`its use, reference is made to the accompanying drawings
`and descriptive matter in which a preferred embodi-
`ment of the invention is illustrated.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`With this description of the invention, a detailed de-
`scription follows with reference being made to the ac-
`oompanying figures of drawing which form part of the
`specification, in which like parts are designated by the
`same reference numbers, and of which:
`FIGS. 1, 2 and 3 are front, side and end views, respec-
`tively,
`illustrating the hybrid inflator of the present
`invention;
`FIG. 4 illustrates a cross-sectional view of the hybrid
`inflator taken along the lines 4-4 of FIG. 1;
`FIG. Sis a cross-sectional view taken along the lines
`5-5 of FIG. 2;
`FIG. 6 is an enlarged fragmentary sectional view of a
`portion of the hybrid inflator sectional view shown in
`FIG. 4;
`'
`FIG. 7 shows hot, ambient and cold tank perfor-
`mances of the hybrid inflator;
`FIG. 8 shows an ambient air bag deployment pressure
`trace; and
`FIG. 9 shows an ambient combustion pressure trace.
`
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`3
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`5,290,060
`
`Referring to the drawings, there is shown a hybrid
`inflator assembly 10 for inflating a vehicle occupant
`restraint such as an air bag. The inflator assembly 10
`comprises a pressure vessel 12 including a storage
`chamber 14 that is filled and pressurized with an inert
`gas such as Argon or Nitrogen to a pressure typically in
`the range of 2000-4000 psi.
`.
`.
`The chamber 14 is defined by an elongated cylindri-
`cal sleeve 16. A fill plug 18 is attached by a circumferen-
`tial weld 20 in sealing relation to a first end 22 of sleeve
`16. A pyrotechnic heater 24 is recessed in sealing rela-
`tion into chamber 14 from a second end 26 of sleeve 16.
`A diffuser 28 extends at substantially a 90° angle from
`the exterior surface 30 of sleeve 16 at a location interme-
`diate the ends 22 and 26 thereof. Diffuser 28 is arranged
`in sealing relation with sleeve 16 and provides a passage
`for the flow of gas from pressure chamber 14 through
`one or more normally closed constricting orifices 32
`that are provided in the wall of sleeve 16.
`The pyrotechnic heater 24 comprises a housing 34
`having an enlarged outer end 36 that mates with the
`second end 26 of sleeve 16. The sleeve 16 and the outer
`end 36 of housing 34 are joined in sealing relation at a
`circumferential weld 38. At the inner end 40 of housing
`34 a central opening or nozzle orifice 42 is provided.
`Orifice 42 is normally covered by a solid metal plug 44
`and a thin metal diaphragm 46, referred to herein as a
`first diaphragm. The diaphragm 46 is joined by a cir-
`cumferential weld 48 at the periphery thereof in sealing
`relation to the inner end 40 of housing 34. The plug 44
`provides back up support for the thin diaphragm 46
`over the entire area thereof, thus enabling the thin dia-
`phragm 46 to withstand the loads of the high pressure
`gas stored in chamber 14. To that end the surface 50 of
`plug 44 adjacent the diaphragm 46, as seen in FIGS. 4
`and 6, is made to be flush with the inner end 40 of hous-
`ing 34, with the plug 44 abutting a shoulder 52 adjacent
`nozzle orifice 42.
`
`Contained within the pyrotechnic housing 34 is a
`pyrotechnic charge 54 of a granular mixture of BKNO3
`and an initiator 56. Initiator 56 is retained within hous-
`ing 34 by a hollow generally cylindrical mounting
`adapter 58. Mounting adapter 58 is located in an open-
`ing 60 in a central location in the outer end 36 of hous-
`ing 34, being sealed therein by an O-ring seal 61. A
`circumferential crimp 62 formed in the outer end 36 of
`housing 34 securely retains the mounting adapter 58 in
`opening 60. Electrical contact pins 57 connect initiator
`56 to collision sensor means (not shown).
`Initiator 56 has a conically shaped portion 63 in en-
`gagement with and matching a similarly shaped conical
`portion provided in the mounting adapter 58. Another
`portion of the mounting adapter 58 forms a crimp 64
`over a reversed conical portion 65 of the initiator 56
`thus retaining the latter securely within the opening 60.
`Pyrotechnic charge 54 is contained within a generally
`cylindrical container 66 having a closed reentrant por-
`tion 68 into which the initiator 56 fits in close but non
`contacting relation. The other end of container 66 is
`closed by a hat shaped container 70. Container 70 in-
`cludes a relatively wide brim 72 at the open end thereof
`that is sealed with an aluminum foil seal 74. Adhesive 76
`may be provided for attaching seal 74 to the brim 72.
`Container 70 contains an igniter material 78. For
`facilitating the insertion of container 70 into the open
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`65
`
`4
`end of container 65 and for effecting a close engage-
`ment with the inner wall surface of the latter, the outer
`peripheral edge of the brim 72 desirably is rounded, as
`best seen in FIG. 6. Sealing between the containers 6
`and 70 may be effected by a suitable sealant 80 such as
`silicone rubber properly cured in known manner. Desir-
`ably, the edge 82 of the open end of container 66 may be
`rounded inwardly, as shown, to conform to the shape of
`the inner wall of the pyrotechnic housing 34 with the
`surface of container 70 remote from foil seal 74 in good
`thermal contact with the inner end wall of housing 34
`and the adjacent end of plug 44.
`Although various pyrotechnic materials may be em-
`ployed for pyrotechnic charge 54 in container 66, a
`preferred material is a granular mixture of 25% by
`weight of Boron and 75% of Potassium Nitrate. This
`mixture has been found to burn with hot flame that is
`suitable for heating the stored gas within chamber 16
`according to the invention.
`The igniter material 78 in container 70 may be any
`granule powder or other material which is stable for
`long periods at temperatures up to 250” F. (l2l° C.),
`will auto ignite at the desired temperature of approxi-
`mately 350° F. (177° C.), and provide a hot gas effluent
`output sufficient to ignite the pyrotechnic charge 54
`within container 66. An igniter material 78 that has been
`found to be satisfactory is du Pont 3031, a product of E.
`I. du Pont de Nemours & Co., Inc. of Wilmington,
`Delaware. Stability over long periods is needed because
`of the expected longevity of use, which may be ten (10)
`years or more of the vehicle in which the hybrid inflator
`10 is installed.
`
`The material of the housing of container 66 may be
`0.010 to 0.020 inch (0.0254 to 0.0508 cm) aluminum or
`steel foil. Adhesive 76 must have high temperature
`adhesive properties up to the temperature of auto igni-
`tion.
`
`The purpose of container 66 and the igniter material
`78 contained therein is to rapidly ignite the inflator 10
`once the auto ignition temperature of the granules of the
`igniter material 78_ is reached. This result is facilitated
`through the arrangement of the igniter material 78 in
`intimate or close thermal contact with the wall of the
`pyrometric housing 34, with the hot gaseous output
`thereof, upon auto ignition, being directed into the py-
`rometric charge 54 in container 66.
`Diffuser 28 comprises a generally cylindrical sleeve
`84 that is joined at one end to the sleeve 16, at a de-
`pressed portion 86 of the surface 30 thereof in which the
`orifice 32 is provided, by a circumferential weld 88. The
`other end of sleeve 84 is joined to and sealed by a gas
`impervious closure plate 90. A thin metal diaphragm 92,
`referred to hereinafter as a second diaphragm, provides
`a seal for orifice 32 in the wall of sleeve 16 which de-
`fines storage chamber 14. Provided in sleeve 84 of dif-
`fuser 28 are a plurality of orifices 94 for dispensing
`inflating gas uniformly from chamber 14 into an air bag
`assembly (not shown).
`A coarse screen or perforated metal sheet indicated at
`96 is provided in the diffuser 28 to cover the diffuser
`orifices 94 to prevent fragments of the diaphragms from
`entering the air bag assembly. If filtering is desired, the
`coarse screen 96 could be replaced with a filter assem-
`bly of wraps of metal and/or ceramic fiber materials
`which are common in the art.
`
`Further filtering is achieved by placing impingement
`filter material indicated at 98 on the inside surface of the
`fill port end plug 18 opposite the central opening 42 or
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`5,290,060
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`5
`nozzle of the pyrotechnic heater 24. Filter 98 would be
`made with woven or matted metal and/or ceramic fi-
`bers which functions by providing a large surface area
`upon which liquid phased particulates entrained in the
`impinging gases may condense.
`If required, a pressure monitoring device (not shown)
`may be included on the fill port end plug 18.
`In the operation of the hybrid gas generator, upon
`receiving an electric signal indicative of the onset of a
`crash, that is, a need for inflation of the air bag, the
`initiator 56 in the pyrotechnic heater 24 fires, igniting
`the pyrotechnic charge 54. As the pressure in the com-
`bustion chamber contained within container 66 rises and
`exceeds the high pressure of the stored gas in chamber
`14, the plug 44 closing the central orifice 42 in the pyro-
`technic housing 34 is unseated. Subsequently, the thin
`diaphragm 46 ruptures since it is unsupported when the
`combustion pressure of the pyrotechnic heater 24 ex-
`ceeds the gas storage pressure in chamber 14. Hot gas
`and particulates from the burning pyrotechnic charge
`54 heat the stored gas causing a rapid pressure rise in the
`storage chamber. When the storage pressure exceeds
`the structural capability of the thin metal diaphragm 92
`in the diffuser 28, it ruptures allowing the heated gas to
`vent through the diffuser orifices 94 into the air bag
`assembly. Between the diffuser diaphragm 92 and the
`storage chamber 14 are one or more constricting ori-
`fices 32 which throttle the flow of gas from the storage
`chamber 14, providing the proper fill rate to the air bag.
`The coarse screen or perforated-metal sheet 96 prevents
`fragments of the diaphragms 46 and 92 from entering
`the air bag assembly. Impingement filter 98 on the fill
`port end plug 18 provides further filtering by condens-
`ing thereon liquid phase particles entrained in the im-
`pinging gases.
`FIG. 7 illustrates hot, ambient and cold tank perfor-
`mances of the hybrid inflator 10.
`FIG. 8 shows an ambient air bag deployment pressure
`trace of the hybrid inflator 10; and
`FIG. 9 shows an ambient combustion pressure trace
`of the hybrid inflator 10.
`In FIG. 9, position 100 on the trace 99 indicates that
`the ignition signal has been received and that the initia-
`tor has fired. Reference numeral 101 shows that the
`
`combustion pressure in pyrotechnic heater 24 exceeds
`the stored gas pressure. Numeral 102 shows the heating
`period of the stored gas in the storage chamber 14.
`Numeral 103 indicates that the second diaphragm 92 has
`ruptured, releasing the heated gas in storage chamber
`14. Numeral 104 indicates the period of gas venting
`from chamber 14.
`Thus, in accordance with the invention, there has
`been provided an improved hybrid inflator that does
`not require glass-to-metal-seals or other complex seal-
`ing methods to maintain the high pressure seal of the
`compressed inert gas storage chamber. Nor does the
`improved hybrid inflator require an actuation means
`(mechanical or pyrotechnic) to open the flow passages
`from the compressed gas storage chamber to the air
`bag. The improved hybrid inflator of the invention,
`moreover, is characterized in dispensing, in its entirety,
`heated gas to the air bag. Additionally, the improved
`hybrid inflator features a centrally located diffuser that
`provides for easier packaging in modules compared to
`end diffusers typically used on hybrid inflators.
`With this description of the invention in detail, those
`skilled in the art will appreciate that modifications may
`be made to the invention without departing from the
`
`6
`it is not intended that the
`spirit thereof. Therefore,
`scope of the invention be limited to the specific embodi-
`ments that have been illustrated and described. Rather,
`it is intended that the scope of the invention be deter-
`mined by the scope of the appended claims.
`What is claimed is:
`1. A hybrid inflator for an air bag comprising,
`a storage chamber for storing inflation gas under high
`pressure, said storage chamber being formed by a
`hollow cylindrical sleeve that is closed at one end
`and open at an opposite end,
`a pyrotechnic heater closing said opposite end of said
`sleeve, said pyrotechnic heater being recessed into
`said sleeve and including a combustion chamber
`having a pyrotechnic charge therein, a nozzle ori-
`fice, a solid plug means abutting a shoulder adja-
`cent said nozzle orifice, and a first diaphragm,
`a diffuser having a plurality of orifices for dispensing
`inflation gas from said storage chamber uniformly
`into an air bag, and
`a second diaphragm,
`said storage chamber being sealed from said diffuser
`by said second diaphragm and being further sealed
`from said combustion chamber by said first dia-
`phragm backed up by said solid plug means against
`the high pressure of the inflation gas stored in said
`storage chamber,
`whereby as the pressure in the combustion chamber
`rises and exceeds the pressure of the stored infla-
`tion gas in said storage chamber upon ignition of
`said pyrotechnic charge, said solid plug is unseated
`with said first diaphragm subsequently rupturing
`since it is unsupported when the pressure in said
`combustion chamber exceeds the pressure in the
`storage chamber, and hot gas from the burning
`pyrotechnic charge heats the stored inflation gas in
`said storage chamber causing a rapid pressure rise
`therein so that when the pressure in said storage
`chamber exceeds the structural capability of said
`second diaphragm rupture of the latter occurs al-
`lowing the heated gas to vent through said diffuser
`orifices into an air bag.
`2. A hybrid inflator as defined by claim 1 wherein
`each of said first and second diaphragms is made of a
`thin metal.
`3. A hybrid inflator as defined by claim 1 wherein
`said hollow cylindrical sleeve is closed at said one end
`by a fill plug means.
`4. A hybrid inflator as defined by claim 3 wherein
`each of said fill plug means and said solid plug means is
`made of metal.
`5. A hybrid inflator as defined by claim 3 wherein
`said fill plug means is welded in sealing relation to said
`one end of said sleeve and said pyrotechnic heater is
`welded to the other end of said sleeve in sealing rela-
`tion.
`6. A hybrid inflator as defined by claim 1 wherein
`said fust diaphragm is welded around the perimeter
`thereof to said pyrotechnic heater in sealing relation to
`said nozzle orifice.
`7. A hybrid inflator as defined by claim 1 further
`including orifice covering means positioned internally
`of said diffuser to prevent fragments of the diaphragms
`from entering the air bag.
`8. A hybrid inflator as defined by claim 8 wherein
`said orifice covering means comprises a coarse screen
`or perforated metal sheet positioned inside the diffuser
`to cover the diffuser orifices.
`
`5
`
`l0
`
`I5
`
`20
`
`25
`
`30,
`
`35
`
`40
`
`45
`
`50
`
`55
`
`65
`
`Page 10 of 12
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`Page 10 of 12
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`

`
`5,290,060
`
`15
`
`35
`
`7
`9. A hybrid inflator as defined by claim 1 further
`including inside said diffuser a filter assembly of wraps
`of metal and/or ceramic fiber materials.
`10. A hybrid inflator as defined by claim 1
`wherein said pyrotechnic heater further includes an 5
`initiator for igniting said pyrotechnic charge in said
`combustion chamber, said initiator being operative,
`upon receiving an electric signal indicative of the
`need for inflation of the airbag, to ignite said pyro-
`technic charge.
`‘
`11. A hybrid inflator as defined by claim 1 wherein
`said pyrotechnic heater further includes in said combus-
`tion chamber auto ignition means including auto igni-
`tion material having an ignition temperature below an
`ignition temperature of said pyrotechnic charge.
`12. A hybrid inflator for an air bag comprising,
`a storage chamber_ for storing inflation gas under high
`pressure, said storage chamber being formed by a
`hollow cylindrical sleeve that is closed at one end
`and open at an opposite end, wherein said hollow 20
`cylindrical sleeve is closed at sad one end by a fill
`plug means,
`a pyrotechnic heater closing said opposite end of said
`sleeve, said pyrotechnic heater being recessed into
`said sleeve and including a combustion chamber 25
`having a pyrotechnic charge therein, a nozzle ori-
`fice, a solid plug means abutting a shoulder adja-
`cent said nozzle orifice, and a first diaphragm,
`wherein said fill plug means is welded in sealing rela-
`tion to said one end of said sleeve and said pyro- 30
`technic heater is welded to the other end of said
`sleeve in sealing relation,
`a diffuser having a plurality of orifices for dispensing
`inflation gas from said storage chamber uniformly
`into an air bag, and
`a second diaphragm,
`said storage chamber being sealed from said diffuser
`by said second diaphragm and being further sealed
`from said combustion chamber by said first dia-
`phragm backed up by said solid plug means against 40
`the high pressure of the inflation gas stored in said
`storage chamber,
`wherein said diffuser includes a cylindrical housing
`having a first end closed off by a plate that is
`welded in sealing relation thereto and having a 45
`second end welded to a portion of said sleeve inter-
`mediate the ends thereof with said second dia-
`phragm positioned between said sleeve and the
`second end of said diffuser housing,
`whereby as the pressure in the combustion chamber 50
`rises and exceeds the pressure of the stored infla-
`tion gas in said storage chamber upon ignition of
`said pyrotechnic charge, said solid plug is unseated
`with said first diaphragm subsequently rupturing
`since it s unsupported when the pressure in said 55
`combustion chamber exceeds the pressure in the
`
`8
`storage chamber, and hot gas from the burning
`pyrotechnic charge heats the stored inflation gas in
`said storage chamber causing a rapid pressure rise
`therein so that when the pressure in said storage
`chamber excess the structural capability of said
`second diaphragm rupture of the latter occurs al-
`lowing the heated gas to vent through said diffuser
`orifices into an air bag.
`13. A hybrid iuflator as defined by claim 9 further
`10 including at least one constricting orifice in the wall of
`said sleeve between said storage chamber and said sec-
`ond diaphragm for throttling the flow of gas from the
`storage chamber upon rupture of said second dia-
`phragm.
`14. A hybrid inflator for an air bag comprising,
`a storage chamber for storing inflation gas under high
`pressure, said storage chamber being formed by a
`hollow cylindrical sleeve that is closed at one end
`and open at an opposite end,
`a pyrotechnic heater closing said opposite end of said
`sleeve, said pyrotechnic heater being recessed into
`said sleeve and including a combustion chamber
`having a pyrotechnic charge therein, a nozzle ori-
`fice, a solid plug means abutting a shoulder adja-
`cent said nozzle orifice, and a first diaphragm,
`a diffuser having a plurality of orifices for dispensing
`inflation gas from said storage chamber uniformly
`into an air bag, and
`a second diaphragm,
`said storage chamber being sealed from said diffuser
`by said second diaphragm and being further sealed
`from said combustion chamber by said first dia-
`phragm backed up by said solid plug means against
`the high pressure of the inflation gas stored in said
`storage chamber,
`wherein said diffuser includes a cylindrical housing
`that is closed at one end and is so attached in seal-
`ing relation, at the other end thereof, to a portion of
`said sleeve intermediate the ends thereof as to ex-
`tend from said sleeve at substantially a 90° angle,
`whereby as the pressure in the combustion chamber
`rises and exceeds the pressure of the stored infla-
`tion gas in said storage chamb‘er upon ignition of
`said pyrotechnic charge, said solid plug is unseated
`with said first diaphragm subsequently rupturing
`since it is unsupported when the pressure in said
`combustion chamber exceeds the pressure in the
`storage chamber, and hot gas from the burning
`pyrotechnic charge heats the stored inflation gas in
`said storage chamber causing a rapid pressure rise
`therein so that when the pressure in said storage
`chamber exceeds the structural capability of said
`second diaphragm rupture of the latter occurs al-
`lowing the heated gas to vent through said diffuser
`orifices into an air bag.
`t
`I
`I
`t
`I
`
`65
`
`Page 11 of 12
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`

`
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`
`
`
`
`
`
`
`DATED
`
`I
`
`;
`
`512901060
`
`March 1 , 1994
`
`|NVENTOR$);
`
`Bradley W. Smith
`
`It is certified that error appears in the above-identified patent and that said Letters Patent is hereby
`corrected as shown below:
`At column 6,
`
`At‘ column 8,
`
`line 9,
`
`line 65, "claim 8" should be -— claim 7 ——.
`"claim 9" should be —- claim 12 ——.
`
`
`
`
`
`
`
`
`
`
`Signed and Sealed this
`
`
`
`BRUCE LEI-[MAN
`
`
`
`Thirteenth Day of September, 1994
`W‘-'
`‘
`@0144 W
`
`
`
`Commissioner of Patents and Trademarks
`
`
`
`Attesting Oflicer
`
`Page 12 of 12
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