United States Patent
`
`[19]
`
`[11] Patent Number:
`
`5,423,571
`
`Hawthorn
`[45] Date of Patent: Jun. 13, 1995
`
`
`
`US005423571A
`
`[54] VEHICLE AIR BAG ASSEMBLY
`
`[75]
`
`Inventor: Laura A. Hawthorn, Vandalia, Ohio
`
`[73] Assignee: General Motors Corporation, Detroit,
`Mich.
`
`[21] Appl. No.: 168,244
`
`[22] Filed:
`
`Dec. 17, 1993
`
`Int. C1.6 ............................................ .. B60R 21/30
`[51]
`[52] U.S. Cl. ............................. .. 230/733; 280/728.3
`[58]
`.Field of Search .................... 280/732, 738, 728 B,
`280/728 R, 731
`
`'
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`............. 280/150 AB
`3,938,826 2/1976 Giorgini et al.
`5,100,172 3/1992 VanVoorhies et al.
`............ 280/738
`5,242,191
`9/1993 Faigle et al.
`........................ 280/731
`
`Primary Examiner—Eric D. Culbreth
`Attorney, Agent, or Firm—Char1es E. Leahy
`
`ABSTRACI‘
`[57]
`A vehicle air bag assembly has a housing mounted be-
`neath an opening in a vehicle panel and holding an
`
`inflator for discharging gas to inflate an air bag for
`deployment through the opening. A door normally
`closes the opening and is forcibly moved out of the
`opening from a closed position to an open position by
`the deploying air bag. The housing also includes a plu-
`rality of apertures communicable with ambient air. A
`flap closes the apertures to prevent communication
`with ambient air so that discharging inflator gas is
`blocked from escaping out through the apertures and is
`fully utilized for initial air bag inflation to open the
`door. A positioning device positions the flap for closing
`the apertures in the housing. The flap is operatively
`connected to the door, such as by having an end secured
`thereto, and is pulled by the opening movement of the
`door to open the apertures. Upon opening movement of
`the door by the deploying air bag, ambient air is aspi-
`rated in through the apertures to augment the volume of
`inflator gas delivered to the air bag, and subsequently
`inflator gas and ambient air may be vented out through
`the apertures.
`
`3 Claims, 1 Drawing Sheet
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`U.S. Patent
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`June 13, 1995
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`5,423,571
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`VEHICLE AIR BAG ASSEMBLY
`
`SUMMARY OF THE INVENTION
`
`The invention relates to a vehicle air bag assembly
`including an inflator housing having aspiration aper-
`tures therein and an air bag for deployment through an
`opening in a vehicle panel closed by a door, and more
`particularly, to an improved air bag assembly in which
`the apertures are opened for aspiration in response to
`opening movement of the door.
`BACKGROUND OF THE INVENTION
`
`It is well known in motor vehicles to have a vehicle
`panel, such as an instrument panel, including an air bag
`deployment opening through which an inflatable air
`bag is deployed. The opening is typically closed by a
`door to normally conceal the undeployed air bag from
`view. A conventional door is hingedly mounted to the
`vehicle panel and separable therefrom so that the inflat-
`ing air bag forcibly moves the door out of the opening
`to permit deployment of the air bag through the open-
`in .
`in air bag assembly includes a housing mounted
`beneath the opening in the instrument panel and an
`inflator for discharging gas to inflate the air bag. Upon
`the vehicle experiencing a predetermined deceleration,
`the inflator discharges gas so that: the air bag forcibly
`opens the door and suddenly deploys through the open-
`ing. This sudden deployment of the air bag, causes a
`rapid pressure drop in the housing as the air bag deploys
`faster than the inflator can discharge gas.
`The prior art teaches that the housing may include
`aspiration apertures therein which are continuously
`open for communication with ambient air. Thus, the
`pressure drop in the housing causes ambient air to be
`aspirated in through the apertures to augment the vol-
`ume of inflator gas delivered to the air bag. Inflator gas
`may also be vented out through these open apertures as
`necessary.
`However, the continuously open apertures may per-
`mit inflator gas to escape out through the apertures
`during initial air bag inflation, thereby reducing the
`inflator gas available to open the door. To compensate
`for this reduction, an uploaded inflator which dis-
`charges greater amounts of inflator gas may be needed,
`thereby adding cost to the air bag assembly.
`The prior art discloses that a closure device, such as
`a flexible flap attached to the air bag or the air bag itself,
`may be used to close she apertures to block inflator gas
`from escaping out through the apertures. The pressure
`of the inflator gas maintains the closure device against
`the wall of the housing to cover the apertures during
`initial air bag inflation. As the air bag deploys out of the
`housing, the apertures are opened to permit aspiration
`of ambient air. By using the flexible flap attached to the
`air bag or the air bag itself as a closure device, the open-
`ing of the apertures is completely in response to the
`movement of the air bag as it inflates.
`.
`Thus, it would be desirable to provide an improved
`air bag assembly in which the apertures are closed when
`the door is in the closed position, and in which the
`apertures are opened in response to opening movement
`of the door, rather than inflation of the air bag, to maxi-
`mize aspiration of ambient air in through the apertures
`to augment the volume of inflator gas delivered to the
`air bag as enabled by the pressure drop in the housing.
`
`According to the invention, a vehicle air bag assem-
`bly has a housing mounted beneath an opening in a
`vehicle panel and holding an inflator for discharging
`gas to inflate an air bag for deployment through the
`opening. A door normally closes the opening and is
`forcibly moved out of the opening from a closed posi-
`tion to an open position by the deploying air bag. The
`housing also includes a plurality of apertures communi-
`cable with ambient air. A flap closes the apertures to
`prevent communication with ambient air so that dis-
`charging inflator gas is blocked from escaping out
`through the apertures and is fully utilized for initial air
`bag inflation to open the door. The flap is operatively
`connected to the door and is pulled by the opening
`movement of the door to open the apertures. Upon
`opening movement of the door by the deploying air
`bag, ambient air is aspirated in through the apertures to
`augment the volume of inflator gas delivered to the air
`bag, and subsequently, inflator gas and ambient air may
`be vented out through the apertures.
`In accordance with another aspect of this invention,
`the flap has an end secured to the door and is suspended
`downwardly therefrom. The housing may comprise a
`wall having a panel attached thereto and spaced apart
`therefrom to cooperatively define a pocket which opens
`subjacent the door. The wall and panel both have a
`plurality of apertures. The wall and panel cooperatively
`position the flap within the pocket for closing the aper-
`tures. The flap is pulled completely out of the pocket by
`the opening movement of the door to open the aper-
`tures.
`—
`
`Accordingly, it is an object, feature and advantage of
`this invention to provide an air bag assembly having a
`housing with aspiration apertures which are closed
`when the door is in the closed position to block dis-
`charging inflator gas from escaping out through the
`apertures to thereby fully utilize the inflator gas for
`initial air bag inflation to open the door, and yet in
`which the apertures are opened in response to opening
`movement of the door to maximize aspiration of ambi-
`ent air in through the apertures to augment the volume
`of inflator gas delivered to the air bag as enabled by a
`pressure drop in the housing caused upon air bag de-
`ployment and to subsequently permit venting of inflator
`gas and ambient air out through the apertures as neces-
`sary.
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`BRIEF DESCRIPTION OF THE DRAWINGS
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`55
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`These and other features, objects, and advantages of
`the present invention will become apparent upon con-
`sideration of the following description of the preferred
`embodiment, appended claims, and accompanying
`drawings in which:
`FIG. 1 is a perspective view of a vehicle interior
`having an instrument panel assembly including a door
`closing an air bag deployment opening; and
`FIG. 2 is a section view taken as indicated along line
`2-2 of FIG. 1 showing the door in the solid line indi-
`cated closed position A,‘ in the phantom line indicated
`partially open position B, and in the phantom line indi-
`cated open position C.
`
`65
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`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Referring to FIG. 1, it is seen that a passenger vehicle
`includes an instrument panel assembly 10 mounted in a
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`vehicle interior rearward of a windshield 12. As shown
`in FIG. 2, the instrument panel assembly 10 includes
`sheet metal stampings 12, 14, 16 which are suitably
`welded and fastened to provide supportive vehicle
`structure to support the instrument panel assembly 10.
`The upper surface of the instrument panel assembly 10
`comprises an instrument panel cover 18 constructed of
`a substrate layer 20 for supporting a foam padding layer
`22 having a decorative skin 24 thereon.‘
`Referring to FIGS. 1 and 2, a generally rectangular
`air bag deployment opening 26 is formed in the instru-
`ment panel cover 18 and is normally closed by a door 28
`having a construction similar to that of the instrument
`panel cover 18, such that the door 28 provides an aes-
`thetically pleasing closure of the opening 26. The door
`28 is hingedly mounted to the instrument panel cover
`18, such as by a hinge strap 30, and is separably secured
`to the instrument panel cover 18, as is well known in the
`art.
`
`As shown in FIG. 2, an air bag assembly 32 includes
`a housing 34. mounted beneath the opening 26 in the
`instrument panel cover 18 and supported sheet metal
`stampings 12, 14. The housing 34 includes a steel reac-
`tion canister portion 36 having a transversely extending
`substantially U-shaped cross section and comprised of a
`curved bottom wall 38 integrally connected to an up-
`standing forward wall 40 and rearward wall 42 being
`closed by parallel end walls (not shown). The forward
`wall 40, rearward wall 42 and end walls define a gener-
`ally rectangular gas discharge opening 44 positioned
`subjacent the opening 26 in the instrument panel cover
`18.
`
`The canister 36 of the housing 34 holds an inflator 46
`for discharging gas through the gas discharge opening
`44 to inflate an air bag 48 upon the vehicle experiencing
`a predetermined rate of deceleration. The inflator 46
`may be of any conventional design, but preferably has
`gas discharge ports (not shown) which direct discharg-
`ing gas upwardly towards the gas discharge opening 44.
`The inflatable air bag 48 is normally stored in the
`canister 36 of the housing 34 in a folded condition and
`has a periphery secured to the gas discharge opening 44
`in a conventional manner.
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`material, but is preferably made of a flexible cloth mate-
`rial similar to that of a conventional air bag.
`Upon actuation,
`the inflator 46 rapidly discharges
`inflator gas towards the gas discharge opening 44 of the
`housing 34 so that pressure is exerted on the air bag 48
`which in turn applies pressure against the bottom of the
`door 28. During initial inflation of the air bag 48, and
`prior to opening of the door 28, the flap 62 is forced
`away from the rearward wall 42 by discharging inflator
`gas. The outer panel 50 restrains the flap 62 and main-
`tains the flap 62 in position within the pocket 54 for
`closing the apertures 60 and blocking discharging infla-
`tor gas from escaping out through the apertures 60 in
`the outer panel 50 so that inflator gas is fully utilized for
`initial air bag 48 inflation to open the door 28.
`The air bag 48 suddenly deploys when the air bag 48
`applies a predetermined pressure to the door 28 and
`moves the door 28 from the solid line indicated closed
`position A to the phantom line indicated open position
`C, as shown in FIG. 2. The flap 62 is rapidly pulled out
`of the pocket 54 by the opening movement of the door
`28 so that the apertures 58, 60 are opened for communi-
`cation with ambient air. It is seen that when the door 28
`is in a partially open position B, the flap 62 has been
`sufficiently moved by the door 28 to fully open the
`apertures 58, 60. It is also seen that in the open position
`C, the flap 62 is restrained against the windshield 12.
`The sudden deployment of the air bag 48 through the
`opening 26 in the instrument panel cover 18, causes a
`rapid pressure drop within the housing 34 as the air bag
`48 deploys faster than the inflator 46 can discharge gas.
`This pressure drop aspirates ambient air in through the
`apertures 58, 60 to augment the volume of gas delivered
`to the air bag 48. The open apertures 58, 60 also subse-
`quently permit venting of the mixture of inflator gas and
`ambient air out through the apertures 58, 60 as neces-
`sary, such as upon the air bag 48 prematurely encoun-
`tering an obstruction during deployment or upon deac-
`tuation of the inflator 46 after full deployment of the air
`bag 48.
`It will be appreciated that since the flap 62 is secured
`to the door 28, the flap 62 progressively, but rapidly,
`begins opening the apertures 58, 60 immediately in re-
`sponse to the opening movement of the door 28 so that
`the advantage of ambient air aspiration is maximized
`during the pressure drop in the housing 34 caused by
`opening movement of the door 28 upon deployment of
`the air bag 48. It will also be appreciated that since the
`flap 62 blocks inflator gas from escaping out through
`the apertures 60 to fully utilize inflator gas during initial
`air bag inflation to open the door 28, a downloaded
`inflator 46 with a decreased capacity for discharging
`gas may be utilized while maintaining reliability in
`opening of the door 28.
`Thus, it is seen that this embodiment of the invention
`provides an improved air bag assembly 32 in which the
`apertures 58, 60 are closed when the door 28 is in the
`closed position A to block discharging inflator gas from
`escaping out through the apertures 60 to fully utilize the
`inflator gas for initial air bag 48 inflation to open the
`door 28, and yet in which the apertures 58, 60 are
`opened in response to opening movement of the door 28
`to maximize aspiration of ambient air in through the
`apertures 58, 60 to augment the volume of inflator gas
`delivered to the air bag 48 as enabled by the pressure
`drop in the housing 34, and to subsequently permit
`venting of inflator gas and ambient air out through the
`apertures 58, 60 as necessary.
`
`The housing 34 further includes an outer panel 50
`located rearwardly of the rearward wall 42 and having
`a lower end portion 52 connected thereto. The rear-
`ward wa1l42 and outer panel 50 are substantially paral-
`lel and are spaced apart to cooperatively define a pocket
`54 having a pocket opening 56 subjacent the free rear-
`ward end of the door 28. The rearward wall 42 and
`outer panel 50 have a plurality of aspiration apertures 58
`and 60, respectively, therein for communicating ambi-
`ent air into the housing 34. The apertures 58 in the
`rearward wall 42 are spaced apart from and preferably
`directly opposing the apertures 60 in the outer panel 50.
`A flexible flap 62 has an end 64 secured to the door
`28, such as by fastening onto the bottom of the door 28
`by rivets 51. When the door 28 is in the closed position
`A, the flap 62 is suspended downwardly from the door
`28 into the pocket 54 and is seated between the rear-
`ward wall 42 and outer panel 50 so that the flap 62 is
`interposed between the apertures 58, 60.
`Thus, the rearward wall 42 and outer panel 50 coop-
`eratively position the flap 62 within the pocket 54 for
`closing the apertures 58, 60 to prevent communication
`with ambient air when the door 28 is in the closed posi-
`tion A. The flap 62 may be made of any impervious
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`position by the deploying air bag, the improvement
`compnsmg:
`the housing comprising at least one wall having a
`panel attached thereto and spaced apart therefrom
`to cooperatively define a pocket which opens sub-
`jacent the door, the wall and panel having a plural-
`ity of apertures;
`a flap means having an end secured to the door and
`being suspended downwardly therefrom;
`the wall and panel cooperatively positioning said flap
`means within the pocket for closing the apertures
`to prevent communication with ambient air when
`the door is in the closed position so that discharg-
`ing inflator gas is blocked from escaping out
`through the apertures and is fully utilized for initial
`air bag inflation to open the door;
`and said flap means being pulled completely out of
`the pocket by the opening movement of the door to
`open the apertures;
`whereby upon opening movement of the door by the
`deploying air bag, ambient air
`is aspirated in
`through the apertures to augment the volume of
`inflator gas delivered to the air bag, and subse-
`quently inflator gas and ambient air may be vented
`out through the apertures.
`2. The improvement of claim 1 further characterized
`by apertures in the wall being directly opposed to the
`apertures in the panel.
`3. The improvement of claim 2 wherein the door has
`a hinged end and an opposite free end and the pocket
`opens subjacent the free end of the door.
`*
`*
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`V
`5
`It will be understood that a person skilled in, the art
`may make modifications to the preferred embodiment
`shown herein within the scope and intent of the claims.
`For example, although the preferred embodiment pro-
`vides an outer panel 50 and a rearward wall 42 for
`positioning the flap 62 to close the apertures 58, 60 from
`communication with ambient air when the door 28 is in
`
`the closed position A, it will be appreciated that other
`positioning devices may also be utilized. Although one
`flap 62 and one outer panel 50 is shown in the preferred
`embodiment, it will be understood that a plurality of
`flaps and a plurality of panels may be provided depend-
`ing on the arrangement of apertures in the housing 34. It
`will also be appreciated that the outer panel 50 or other
`device for positioning the flap 62 may be connected to
`vehicle structure other than the canister 36.
`While the present invention has been described as
`carried out in a specific embodiment thereof, it is not
`intended to be limited thereby but is intended to cover
`the invention broadly within the scope and spirit of the
`appended claims.
`The embodiments of the invention in which an exclu-
`
`sive property or privilege is claimed are defined as
`follows:
`1. In a vehicle air bag assembly having a housing
`mounted beneath an opening in a vehicle panel and
`holding an inflator for discharging gas to inflate an air
`bag for deployment through the opening, and a door
`normally closing the opening and being forcibly moved
`out of the opening from a closed position to an open
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