IPR 2016-01794
`American Vehicular Sciences
`Exhibit 2026
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`

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`U.S. Patent
`
`Apr. 2, 1991
`
`Sheet 1 of 2
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`US. Patent
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`Apr. 2, 1991
`
`Sheet 2 of 2
`
`5,004,586
`
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`

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`GAS GENERATING APPARATUS FOR
`INFLATING AIR BAG
`
`BACKGROUND OF THE INVENTION
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`5
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`1. Field of the Invention
`
`This invention relates to a gas generating apparatus
`used for inflating an air bag such as one used for a safety .
`10
`apparatus for protection against collison, life bag, rub-
`ber boat, escape chute, etc. More particularly, this in-
`vention concerns a gas generating apparatus for inflat-
`ing an air bag whereby any shortfall in the quantity of
`gas required for inflating the air bag can be overcome
`by replenishing the air bag with air.
`2. Statement of the Prior Art
`
`15
`
`Conventionally, in a passenger car, a safety apparatus
`adapted to protect passengers against physical shock at
`the time of a collision comprises an air bag with a vol-
`ume of 60 liters and a gas generating apparatus which
`inflates this air bag, the gas generating apparatus being
`filled either with an explosiver or a gas generating agent
`comprising similar constituents which is ignited and
`burnt at the time or a collision so as to immediately
`inflate the air bag with a gas generated thereby, thus
`protecting the driver from the effects of the collision,
`and preventing him from being seriously injured.
`In such an apparatus, the quantity of gas generating
`agent required for inflating the air bag is between 70 and
`100 g, and the total weight of the body of the gas gener-
`ator is between 600 and 1100 g. With the above appara-
`tus, the air bag is inflated merely by the generation of
`gas upon combustion of the gas generating agent; there-
`fore, even an air bag with a 60-1iter volume uses from 70
`to 100 g of the generated gas, which is a relatively large
`amount for the gas inflation and, consequently,
`the
`volume of the combustion chamber in the body of the
`gas generator has to be increased to raise the gas tem-
`perature and the temperature inside the gas generating
`unit by combustion of a relatively large amount of gas
`generating agent since the volume of the combustion
`chamber in the gas generating unit also has to be in-
`creased, it is relatively large and heavy, and this in-
`volves such hazards as the possibility of passengers
`being burnt.
`If the gas generating apparatus is reduced in size and
`weight with a corresponding reduction in the quantity
`of gas generating agent used therein, the air bag is not
`inflated to a sufficient extent and its function as a safety
`apparatus in time of collision is thereby compromised.
`Therefore, the shortfall in the quantity of gas generated
`needs to be overcome by supplementing the gas or the
`like.
`
`For this purpose it is conceivable to incorporate in
`the gas generating apparatus an air ejector for replenish-
`ing air by ejecting a high-pressure gas or a vapor ejec-
`tor. However, since the primary high pressure gas in
`these kind of ejector has a pressure as low as 10 kg/cm2
`or less, such an ejector also needs to be relatively in-
`creased large in size to be effective when used with such
`an air bag in a safety apparatus of the type described in
`order that a sufficient amount of air can be sucked in
`some tens of milliseconds.
`
`Accordingly, such a gas generating apparatus is inev-
`itably increased in size and weight and this means that it
`remains impossible for this type of bag to be used as an
`air bag for an automobile.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a vertical sectional view of an embodiment
`of the gas generating apparatus for inflating an air bag
`according to the present invention;
`FIG. 2 is a top plan view thereof.
`FIG. 3 is a perspective view of the new gas generat-
`ing apparatus.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Referring now to FIGS. 1-2, a description will be
`made of an embodiment of the present invention.
`As illustrated in FIGS. 1—2, reference numeral 1 de-
`notes a housing body one end of which is choked and
`the other end opened, which includes a cylinder portion
`2 with a small diameter and a cylinder portion 4 with a
`small diameter connected to an opening end of this
`cylinder portion 2 by means of a flange portion 3. A
`multiplicity of air intakes 5 comprising slotted holes
`arrayed in a ring-like configuration are provided in the
`flange 3, and an inner circumferential wall surface 40 of
`the cylinder portion 4 with a large diameter is formed
`into a tapered face whose greater diameter is at opening
`end. Reference numeral 6 indicates a flange which is
`formed integrally with the outer periphery of the large-
`diameter cylinder portion 4, and an opening of the air
`bag (not shown but the relative location of which is
`shown by dotted line B) can be mounted on this flange.
`A threaded portion 7 which is concentrically formed
`at the center of the choked portion inside the housing
`body 1 is screwed into the cylinder 8 such as to face the
`opening thereof. This cylinder 8 forms a combustion
`chamber 9 wherein its entire outer circumferential wall
`on the closed side is provided with a multiplicity of
`combustion gas orifices 10. A gas generating agent (not
`shown) in the form of either granules or pellets, which
`is composed of an oxidizing agent such as sodium azide
`and sodium nitrate or potassium perchlorate, is stored in
`the combustion chamber 9. Reference numeral 11
`means for receiving a gas generating agent igniting
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`1
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`5,004,586
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`2
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`SUMMARY OF THE INVENTION
`
`The present invention aims to solve such problems as
`those described above, and an object of the present
`invention is to provide a small, lightweight and safe gas
`generating apparatus for inflating an air bag wherein the
`quantity of gas generating agent used for inflating the
`air bag is reduced without resulting in any attendant
`disadvantages.
`the high-pressure gas is
`In the present invention,
`generated when the gas generating agent in a combus-
`tion chamber is combusted, and this high-pressure gas is
`ejected in the direction of an opening from an annular
`nozzle into a mixing chamber, so that air is sucked from
`air intakes into the mixing chamber by virture of the
`ejector effect. This sucked air is mixed with and cools
`the gas and flowsinto the air bag to inflate the same.
`Thus since the nozzle and air intakes are formed on
`the outer periphery of the housing body, a large quan-
`tity of outside air can be sucked positively owing to the
`ejector effect obtained by the ejecting gas,. Conse-
`quently, it is possible to decrease the quantity of gas
`generating agent used and to reduce the size and weight
`of the gas generating apparatus in proportion to the
`decrease in volume of the combustion chamber.
`
`device mounted at the center of the threaded portion 7.
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`3
`In FIG. 1, reference numeral 12 denotes a cylindrical
`partition which is concentrically disposed around the
`periphery of the cylinder portion 8 inside the large-
`diameter cylinder portion 4 of the housing body 1 in
`such a manner as to surround the gas orifices 10. A
`flange 13 of the cylindrical partition 12 is integrally
`connected with the outer periphery the cylinder 8 on
`the choked side thereof by welding, and a filter 14 is
`provided inside the partition 12 in order to filtrate com-
`bustion residues in a gas. Further, the outer circumfer-
`ential wall surface 12a of the partition 12 is so formed as
`to have a tapered face which is in parallel with the inner
`circumferential wall surface 40 of the cylinder portion
`4, wherein the inner circumferential wall 4a and outer
`circumferential wall surface 12a form a mixing chamber
`15 for a combustion gas and air which is sucked from
`the intake 5. A nozzle 16 is formed into a ring-like 'con-
`figuration between the inner circumferential angle por-
`tion of the flange portion 3 in close proximity to the air
`intakes 5 of the housing body 1 and the opening end
`portion of the cylindrical partition 12 which faces this
`inner circumferential angle portion, whereby a high-
`pressure combustion gas is throttled and ejected into the
`mixing chamber 15 at high speed.
`The ratio of the entire sectional area of the air intakes
`5 to the sectional area of the throat of the nozle 16 is
`preferably set at least 10:1 or more and, more prefera-
`bly, 50:1 or more. The ratio L/D of the length L of the
`mixing chamber 15 which is formed by the inner cir-
`cumferential wall surface 4a and the outer circumferen-
`tial wall surface 12a to the space D between these wall
`surfaces is set between 1:1 and 1:8, and the ratio of air
`taken thereinto becomes maximum when it is set be-
`tween 1:5 and 1:7.
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`In a gas generating apparatus configured as described
`above, a high-pressure gas with a pressure of 50 to 200
`kg/cm2 is produced when the gas generating agent is
`ignited by the igniting device 11 and combusted in the
`combustion chamber 9. This high-pressure gas flows
`from the orifices 10 into the cylider 12 whereas solid
`residues in the gas is removed when passing through the
`filter 14, and the gas is ejected from the nozzle 16 into
`the mixing chamber 15 at high speed. Since the pressure
`in the opening portion A of the air intake 5 which is
`open to the mixing chamber 15 is reduced remarkably to
`less than the atmospheric pressure at this moment, a
`large quantity of air from the inside of an automobile is
`sucked in through the air intakes 5. This sucked air is
`mixed with the mixing chamber 15 with the high-tem-
`perature, high-pressure gas ejected from the nozzle 16,
`whereby the gas is cooled and an air bag, (not shown
`except by its general location at B) is instantly inflated
`(within some tens of milliseconds) with the air which is
`discharged thereinto from an opening 150 of the mixing
`chamber 15.
`
`It should be noted that the lower the pressure in the
`combustion chamber 9 is, the larger the ratio of the
`quantity of sucked air to the quantity of combustion gas
`becomes. However, since the speed of the entire mix-
`ture of gas flowing into the air bag is reduced, resulting
`in the delay of inflation of the air bag, the pressure in the
`combustion chamber is preferably set at between 50 and
`200 kg/cm2 in order that the air bag can be completely
`inflated in the steering compartment in such a short time
`as some tens of milliseconds. The ratio of the total sec-
`tional area of the air intakes 5 to the total sectional area
`of the throat of the nozzle 16 is set at least 50:1 or more.
`Further, the ratio L/D is preferably set between 5:1 and
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`5,004,586
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`7:1. Thus, the mixing rate of air becomes high, with the
`result that cooling of the combustion gas and conse-
`quently cooling of the gas generating apparatus itself
`can be performed effectively. This allows the gas gener~
`ating apparatus to be reduced in size and weight, since
`the temperatures of the gas and gas generating appara-
`tus are lower and the quantity of gas generating agent
`used is reduced. In addition, safety of the apparatus is
`improved due to the absence of any danger of burns or
`other hazards.
`
`The pressure inside the automobile can be prevented
`from rising by virtue of the air bag being inflated in a
`conventional manner, because the air in the automobile
`is sucked into the air bag during its expansion. Also,
`costs can be reduced in proportion to the decrease in the
`quantity of gas generating agent used.
`It is considered that 20 to 30 g of the gas generating
`agent will fully inflate the air bag, since the gas generat-
`ing apparatus of the embodiment according to the pres-
`ent invention positively sucks air, whereas a conven-
`tional gas generating apparatus requires 70 to 100 g of
`gas generating agent to inflate an air bag with volume of
`60 liters provided for a driver’s seat.
`It should be noted that a gas generating apparatus
`according to the present invention is not limited to the
`one having the asrrangement described in the above
`embodiment.
`
`In addition, a gas generating apparatus according to
`the present invention can be applied not only to an air
`bag for the driver’s seat of an automobile but can also be
`employed as a gas generating apparatus for inflating an
`air bag for an assistant's seat,
`life boat, rubber boat,
`escape chute, etc. where a larger Quantity of air is re-
`quired for inflating.
`_ Thus, in accordance with the present invention, a gas
`generating apparatus is arranged such that a combustion
`chamber for a gas generating agent is disposed at the
`center of a housing body, and air intakes, a nozzle for
`gas ejection, and a mixing chamber for mixing sucked
`air and ejected gas are provided on the outer peripheral
`side of the housing. Therefore, a large quantity of out-
`side air can be positively sucked into the air bag during
`an operation of the gas generating apparatus and, conse-
`quently the quantity of the gas required for inflating the
`air bag can be sufficiently maintained even if there is an
`inherently insufficient quantity of the gas generating
`agent employed for this purpose, thereby, allowing the
`volume of the combustion chamber to be reduced in
`parallel with the lower quantity of gas generating agent
`used. A further effect is that the lower gas temperatures
`offer an improved level of safety, since the gas and air
`may flow into the air bag after being mixed with each
`other.
`What is claimed is:
`
`1. A gas generating apparatus for inflating an air bag,
`COmpl’lSlng:
`a housing body (1) having opposite sides, one of
`‘ which opens toward an air bag when a portion (6)
`of the body is connected to such air bag;
`a combustion chamber (9) formed centrally within
`said housing body, wherein high-pressure gas is
`generated upon combustion of a gas generating
`agent contained within the body;
`the housing body having a partition (12) which forms
`a mixing chamber (15) in ring-like configuration
`concentrically disposed so as to be spaced apart
`from a discharge (150) opening of said housing
`body by a desired interval, said combustion cham-
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`5
`ber communicating with said mixing chamber
`whereby said high-pressure gas from said combus-
`tion chamber is introduced into said mixing cham-
`ber;
`a nozzle (16) of ring-like configuration provided
`wherein said housing body for ejecting said high-
`pressure gas flowing from said combustion cham-
`ber toward an entrance opening of said mixing
`chamber formed by said partition; and
`an air intake means (5) formed in said housing body in
`close proximity to said nozzle and opening from
`the side of the housing body opposite from such air
`bag, whereby said high pressure gas ejected by said
`nozzle causes air to be drawn through said air in-
`take means into said mixing chamber and mixed
`therein with said high-pressure combustion gas for
`cooling thereof.
`2. A gas generating apparatus for inflating an air bag
`according to claim 1, wherein:
`said housing body has a cross-section of a substan-
`tially U-shaped form with one end opposite from
`such air bag choked and the other end providing
`said discharge opening (15 a), comprising a first
`cylinder portion (2) having a smaller diameter and
`a further cylinder portion (4) having a larger diam-
`eter connected by a flange portion (3) to the open-
`ing of said cylinder portion with a small diameter;
`said flange portion being provided with a plurality of 30
`air intake ports (5) formed by slotted holes consti-
`tuting said air intake means, said slotted holes being
`arrayed in a ring-like configuration; and
`said further cylinder portion having an inner circum-
`ferential wall formed with a tapered face of diame-
`ter widening toward a direction from said flange
`portion toward said discharge opening.
`3. A gas generating apparatus for inflating an air bag
`according to claim 2, wherein a flange mount (16) is
`formed integrally with the outer'circumference of said
`first cylinder portion to allow the opening of such air
`bag to be mounted on said flange mount.
`4. A gas generating apparatus for inflating an air bag
`according to claim 1, wherein said combustion chamber
`comprises a further cylinder (8), one end thereof being
`choked, screwed to a threaded portion (7) concentri-
`cally formed at the center of said body housing.
`5. A gas generating apparatus for inflating an air bag
`according to claim 4, wherein said further cylinder (8)
`comprises a multiplicity of combustion gas orificespro-
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`5,004,586
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`6
`vided around the entire circumference of a circumferen-
`tial wall at said choked end (8) of said further cylinder.
`6. A gas generating apparatus for inflating an air bag
`according to claim 2, wherein said partition (12) is lo-
`cated within said further cylinder portion (4) and is
`concentrically disposed at the outer periphery of said
`further cylinder (4) in such a manner as to surround said
`combustion gas orifices.
`7. A gas generating apparatus for inflating an air bag
`according to claim 6, wherein said partition (12) is inte-
`gral with a flange projection (13) and is welded by
`means of the flange projection to the choked end of said
`further cylinder (8).
`8. A gas generating apparatus for inflating an air bag
`according to claim 1, further comprising a filter (14) for
`the filtration of combustion residues in said combustion
`gas, said filter being provided within said partition (12).
`9. A gas generating apparatus for inflating an air bag
`according to claim 2, wherein said partition has an outer
`circumferential wall (12a) having a tapered face which
`is in parallel with an inner circumferential wall of said
`further cylinder portion (4) of said housing body.
`10. A gas generating apparatus for inflating an air bag
`according to claim 2, wherein said combustion chamber
`is formed so as to mix said combustion gas with air
`sucked from said air intake means between inner cir-
`cumferential wall of said further cylinder portion (4)
`and an outer circumferential wall of said partition (12) .
`11. A gas generating apparatus for inflating an air bag
`according to claim 2 wherein said nozzle (16) is formed
`between an inner circumferential angle portion of said
`flange portion (3) in close proximity to said air intake
`means (5), whereby said combustion gas is throttled to
`eject toward said mixing chamber at high speed.
`12. A gas generating apparatus for inflating an air bag
`according to claim 1, said nozzle (16) having a throat,
`wherein the ratio of the sectional area of said air intake
`means to the sectional area of said throat is at least 10:1.
`13. A gas generating apparatus for inflating an air bag
`according to claim 12, wherein the ratio of the total
`sectional area of said air intake means to the sectional
`area of said nozzle throat is at least 50:1.
`14. A gas generating apparatus for inflating an air bag
`according to claim 1, wherein the ratio L/D of a length
`L formed by inner circumferential and outer circumfer-
`ential walls of said mixing chamber to an interval D
`between said walls is between 1:1 and 8:1.
`15. A gas generating apparatus for inflating an air bag
`according to claim 14, wherein said ration L/D is be-
`tween 5:1 and 7:1.
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`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`PATENTND.
`
`: 5,004,586
`
`DATED
`
`: April 2, 1991
`
`|NVENTOR(S): M. Hayashi et al
`
`Col. 5,
`
`line 6, replace "wherein" with -—within-—;
`
`line 39, replace "(16)" with —-(6)——.
`
`
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`
`
`It is certified that error appears in the above-identified patent and that said Letters Patent is hereby
`corrected as shown below:
`
`
`
`Signed and Sealed this
`
`Twenty-fifth Day of August, 1992
`
`Arrest:
`
`DOUGLAS B. COMER
`
`Attesn'ng Officer
`
`Acting Commissioner of Patents and Trademarks
`
`