U.S. patent application number 09/416991 was filed with the patent office on 2001-11-29 for air bag module with variable inflation..
This patent application is currently assigned to Alex Scott Damman. Invention is credited to ALSUP, THERIAL LEVELL, DAMMAN, ALEX SCOTT, STARNER, ALLEN RICHARD.
Application Number | 20010045734 09/416991 |
Document ID | / |
Family ID | 23652157 |
Filed Date | 2001-11-29 |
United States Patent
Application |
20010045734 |
Kind Code |
A1 |
DAMMAN, ALEX SCOTT ; et
al. |
November 29, 2001 |
AIR BAG MODULE WITH VARIABLE INFLATION.
Abstract
This present invention provides variable deployment performance
by controlling the quantity and fluid flow path of the inflator gas
into or out of an air bag module according to the present
invention. The air bag module includes a vent opening and a cushion
retainer diffuser including a plurality of diffuser openings which
permits fluid communication between an annular cavity and an air
bag cushion. The vent opening provides a fluid path for the
inflator gas to flow from the annular cavity to outside of the air
bag module. For full level deployment, the vent opening is closed
and therefore the inflator gas is not permitted to flow away from
the air bag module but instead flows into the air bag cushion. For
low level deployment, the volume of inflator gas which flows into
the air bag cushion is controlled by selecting the ratio between
the cross-sectional area of the diffuser openings and the
cross-sectional area of the vent opening. For example, for reduced
low level deployment, the cross-sectional area of the vent opening
is increased in relation to the cross-sectional area of the
diffuser openings. Conversely, for increased low level deployment,
the cross-sectional area of the vent opening is decreased in
relation to the cross-sectional area of the diffuser openings.
Accordingly, the selective control of the ratio acts as a tuning
mechanism by which different low level inflator outputs can be
achieved. Deployment module levels between low level and high level
can be achieved by controlling the timing of when the vent opening
is closed.
Inventors: |
DAMMAN, ALEX SCOTT;
(Hilliard, OH) ; STARNER, ALLEN RICHARD;
(Springboro, OH) ; ALSUP, THERIAL LEVELL; (Dayton,
OH) |
Correspondence
Address: |
KATHRYN A MARRA
DELPHI TECHNOLOGIES INC
LEGAL STAFF PO BOX 5052
MAIL CODE: 480-414-420
TROY
MI
480075052
|
Assignee: |
Alex Scott Damman
|
Family ID: |
23652157 |
Appl. No.: |
09/416991 |
Filed: |
October 13, 1999 |
Current U.S.
Class: |
280/736 ;
280/728.3 |
Current CPC
Class: |
B60R 21/276 20130101;
B60R 21/217 20130101; B60R 2021/2765 20130101 |
Class at
Publication: |
280/736 ;
280/728.3 |
International
Class: |
B60R 021/20 |
Claims
What is claimed is:
1. An air bag module for restraint of an occupant in vehicle, the
air bag module comprising: an air bag cushion; an inflator being
activatable to discharge inflator gas for inflating the air bag
cushion, the inflator having a plurality of discharge ports through
which the inflator gas is discharged; a diffuser having a cavity
disposed adjacent the inflator, the diffuser having a plurality of
diffuser openings formed therein to provide fluid communication
between the cavity and the air bag cushion, the plurality of
diffuser openings providing a first fluid path between the inflator
and the air bag cushion, the diffuser openings having a first
cross-sectional area; a plate disposed about the inflator, the
plate including a vent opening which provides a second fluid path
to expel the inflator gas from the air bag module, the vent opening
having a second cross-sectional area; an actuator assembly
including a movable member being movable relative to the vent
opening for restricting fluid flow through the vent opening, the
actuator assembly having an actuator for moving the movable member
under predetermined first deployment conditions; and wherein the
air bag module has a selectable ratio between the first
cross-sectional area and the second cross-sectional area, the
selectable ratio being a predetermined value so that the volume of
inflator gas discharged into the air bag cushion and the volume of
inflator gas expelled out through the vent opening of the plate is
controlled.
2. The air bag module as set forth in claim 1, wherein the
plurality of diffuser openings are disposed radially around an
annular side wall of the diffuser.
3. The air bag module as set forth in claim 1, wherein the plate is
disposed below the diffuser, the vent opening being disposed below
the plurality of diffuser openings and the plurality of discharge
ports.
4. The air bag module as set forth in claim 1, wherein the actuator
is a pyrotechnic device.
5. The air bag module as set forth in claim 1, wherein the actuator
is capable of generating pressure for moving the member.
6. The air bag module as set forth in claim 1, wherein the actuator
assembly is actuated under full level deployment conditions so that
the inflator gas flows to the air bag cushion and is prevented from
flowing according to the second fluid path.
7. The air bag module as set forth in claim 1, wherein the
selectable ratio between the first cross-sectional area of the
diffuser openings and the second cross-sectional area of the vent
opening is increased to provide greater inflation of the air bag
cushion due to a greater volume of inflator gas flowing into the
air bag cushion.
8. The air bag module as set forth in claim 1, wherein the
selectable ratio between the first cross-sectional area of the
diffuser openings and the second cross-sectional area of the vent
opening is decreased to provide a lesser level of inflation of the
air bag cushion.
9. The air bag module as set forth in claim 1, wherein the first
cross-sectional area is increased by increasing the number of
diffuser openings or by varying the dimensions of the diffuser
openings.
10. The air bag module as set forth in claim 1, wherein the first
cross-sectional area is decreased by decreasing the number of
diffuser openings or by varying the dimension of the diffuser
openings.
11. The air bag module as set forth in claim 1, wherein the
actuator assembly is opened at a predetermined time during
inflation of the air bag cushion, wherein the predetermined time
for moving the member is determined in response to a predetermined
condition of the vehicle.
12. The air bag module as set forth in claim 1, wherein the cavity
is substantially annular.
13. The air bag module as set forth in claim 1, wherein the plate
has an opening for receiving the inflator therein.
14. The air bag module as set forth in claim 1, wherein the
diffuser comprises a cushion retainer for securing the air bag
cushion to a base plate.
15. The air bag module as set forth in claim 1, wherein the plate
comprises a base plate for securing the air bag module to the
vehicle.
16. The air bag module as set forth in claim 1, further including a
pad retainer having a first surface and a second surface, the first
surface being disposed adjacent the plate and the second surface
being disposed adjacent an adapter plate, wherein the pad retainer,
the plate and the adapter plate include openings formed therein,
the openings defining the vent opening.
17. The air bag module as set forth in claim 1, wherein the
actuator assembly includes a housing for retaining the actuator, a
liner and the movable member.
18. The air bag module as set forth in claim 1, wherein the movable
member comprises a slide.
19. The air bag module as set forth in claim 1, wherein the movable
member comprises a stopper which plugs the vent opening upon
actuation of the actuator.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to vehicle
supplemental inflatable restraint systems and, more particularly,
to an air bag module that provides variable output inflation of an
air bag cushion from a single inflator.
BACKGROUND OF THE INVENTION
[0002] Driver side or passenger side supplemental inflatable
restraint (SIR) systems typically include an air bag stored in a
housing module within the interior of the vehicle in close
proximity to either the driver or one or more passengers. SIR
systems are designed to actuate upon sudden deceleration so as to
rapidly deploy an air bag to restrain the movement of the driver or
passengers. During deployment, gas is emitted rapidly from an
inflator into the air bag to expand it to a fully inflated
state.
[0003] Air bag passive restraint systems include an inflator, which
produces gas to inflate the air bag cushion. Known inflators for
air bag modules are generally of three types. One type is the pure
gas inflator wherein a pressure vessel contains stored pressurized
gas. The pressure vessel communicates with the cushion through
various types of rupturable outlets or diaphragms. Another type is
the gas generator wherein a propellant is ignited and the resultant
gas created flows through an outlet to the cushion. A third type is
the hybrid or augmented type. This type includes a pressure vessel
containing stored pressurized gas and a gas generator. When the
generator is ignited, the resultant gas flows with and heats the
stored gas going to the cushion through the pressure vessel
outlet.
[0004] It is also known to inflate the cushion at a relatively low
rate under low level deployment conditions, such as a sudden low
level deceleration, and at a relatively high rate under high level
deployment conditions, such as a sudden high level deceleration.
Devices are known which provide primary inflation (reduced
inflation) and full level inflation using a single gas vessel with
two separate gas heaters. Primary inflation is accomplished by
actuating the gas vessel and heating the gas at a specified reduced
level. Full level inflation is accomplished by actuating a second
separate heater located at the bottom of the gas vessel to heat the
gas at a greater level. This second heater is deployed at the same
time or a delayed time as the primary heater to provide fall level
inflation. It is also known in the art to use a system having two
discrete inflators to accomplish dual level inflation. In these
types of systems, two discrete inflators are deployed at the same
time or at a delayed time depending upon the severity of the sudden
deceleration.
SUMMARY OF THE INVENTION
[0005] This invention offers advantages and alternatives over the
prior art by providing an air bag module which offers variable
deployment performance by controlling the quantity and fluid flow
path of the inflator gas into or out of the air bag module. The air
bag module includes an inflator for generating inflator gas for
inflation of an air bag cushion. The air bag module includes a
cushion retainer (diffuser) having a vent opening and an annular
cavity which is disposed about the inflator. The cushion retainer
includes a plurality of diffuser openings which permits fluid
communication between the annular cavity and the air bag cushion.
The air bag module further includes an annular base plate, a pad
retainer, and an adapter plate disposed about the inflator. The
annular base plate, pad retainer, and adapter plate include
openings which define a vent opening to provide a fluid path for
the inflator gas to flow from the annular cavity to outside of the
air bag module. For full level deployment, the vent opening is
closed and therefore the inflator gas is not permitted to flow away
from the air bag module but instead flows into the air bag cushion.
The degree of reduced level deployment of the air bag cushion is
dependent upon the volume of the gas directed away from the air bag
cushion. In accordance with the present invention, the volume of
inflator gas which flows into the air bag cushion is controlled by
selecting the ratio between the cross-sectional area of the
diffuser openings and the cross-sectional area of the vent opening.
For example, for a low reduced level deployment, the
cross-sectional area of the vent opening is increased in relation
to the cross-sectional area of the diffuser openings. This may be
achieved in a variety of ways, including reducing the
cross-sectional area of the diffuser openings or by reducing the
number of diffuser openings or by increasing the relative vent of
cross-sectional area. Conversely, for increased low level
deployment, the cross-sectional area of the vent opening is
decreased in relation to the cross-sectional area of the diffuser
openings and/or the number or size of the diffuser openings are
increased so that a greater volume of inflator gas is directed
toward the air bag cushion. Accordingly, the selective control of
the ratio acts as a tuning mechanism by which different low level
inflator outputs can be achieved.
[0006] The air bag module also includes an actuator assembly
including a movable member which is movable relative to the vent
opening for restricting fluid flow through the vent opening under
predetermined deployment conditions. The actuator assembly has an
actuator for moving the movable member and in an exemplary
embodiment the actuator comprises a pyrotechnic device. In the
illustrated and exemplary embodiment, the movable member comprises
a slide mechanism or a stopper mechanism which closes the vent
opening under predetermined deployment conditions and prevents the
inflator gas from flowing away from the air bag cushion.
Furthermore, controlling the timing of the vent closure provides a
way to obtain variable inflation between the low and high level
performance.
[0007] The above-described and other features and advantages of the
present invention will be appreciated and understood by those
skilled in the art from the following detailed description,
drawings, and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present invention will now be described, by way of
example only, with reference to the accompanying drawing in
which:
[0009] FIG. 1 is a sectional side view of an air bag module
embodying a first embodiment of the present invention shown during
full level deployment of an air bag cushion;
[0010] FIG. 2 is a sectional side view of the air bag module of
FIG. 1 shown during reduced level deployment of the air bag
cushion;
[0011] FIG. 3 is sectional side view of an air bag module embodying
a second embodiment of the present invention shown during full
level deployment of an air bag cushion; and
[0012] FIG. 4 is sectional side view of the air bag module of FIG.
3 shown during reduced level deployment of the air bag cushion.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Referring to the FIGS. 1-2, an air bag module according to a
first embodiment is generally designated at 10. The air bag module
10 is suitably mounted to a central hub of a steering wheel (not
shown). The air bag module 10 includes an inflator 12 for
generating inflator gas upon the sensing of predetermined vehicle
conditions, i.e. rapid deceleration, to inflate an air bag cushion
14. Inflator 12 has a predetermined number of vent ports 16
radially disposed within inflator 12. An annular cushion retainer
diffuser 18 is disposed about the inflator for directing gases from
the inflator 12 to the air bag cushion 14. The cushion retainer 18
further includes a predetermined number of diffuser openings 20
which fluidly communicate with the air bag cushion 14 and permit
inflator gas to pass into and inflate the air bag cushion 14 under
deployment conditions. The inflator 12 shown is commonly used for
an air bag module 10 installed in a driver side of a vehicle to
protect the driver thereof. One skilled in the art, however, will
recognize that the air bag module 10 described hereinafter may be
used for other passive restraints, i.e., passenger side air bag
modules and side impact air bag modules.
[0014] Upon actuation of the inflator 12 in response to a sudden
deceleration of a motor vehicle, heated gas discharges from the
inflator vent ports 16 disposed in the inflator 12 to inflate the
air bag cushion 14.
[0015] A controller (not shown), e.g., a sensing and actuating
system, generates an ignition signal to the inflator 12. In
response to the sensed signals, the controller provides an ignition
signal to the inflator 12 to initiate deployment inflation of the
air bag cushion 14 in accordance with a predetermined level of
deceleration. In response to the ignition signal, the inflator 12
releases an appropriate predetermined volume of gas into the air
bag cushion 14 through the vent ports 16 of the inflator 12. The
level of deployment of the air bag cushion 14 is partially
dependent upon on the actuation of a slide actuator assembly 30
slidably arranged to selectively restrict or prevent gas flow away
from the air bag cushion 14, as will be described hereinafter. For
example, for the lowest level of module deployment energy, no
action is required by the slide actuator assembly 30.
[0016] Inflator 12 may be of any conventional construction for
generating inflator gas to inflate the air bag cushion 14.
Advantageously, the inflator 12 is preferably a single stage
inflator which outputs inflator gas to inflate the air bag cushion
14. The inflator 12 has a generally cylindrical body portion and a
flange 34 that suitably secures to an adapter plate 40. The vent
ports 16 are preferably formed in a side wall 42 of inflator 12 and
extend around side wall 42 of inflator 12 in a radial manner and it
is understood that the number and dimension of the vent ports 16
may be varied according to the precise application and
configuration of the inflator 12. An initiator or pyrotechnic
device (not shown) disposed within the inflator 12 ignites
pyrotechnic material which generates heated gas that discharges
through the discharge vent ports 16 to inflate the air bag cushion
14.
[0017] As shown in FIG. 1, the adapter plate 40 supports both the
inflator 12 and the slide actuator assembly 30. The inflator 12 is
mounted within a central opening 46 of the adapter plate 40 by
known techniques, including the use of a plurality of threaded
studs (not shown) extending from a bottom surface thereof. The air
bag module 10 further includes an annular base plate 60, formed of
a rigid material, having a central opening 62 for receiving the
inflator 12 therethrough. A pad retainer 70 is secured to a bottom
surface of the base plate 60 to provide a means for securing an air
bag cover or pad (not shown) to the base plate 60. The pad retainer
70 also includes a central opening 72 for receiving the inflator 12
to permit the inflator 12 to extend into the air bag cushion
14.
[0018] The adapter plate 40 includes a first slot 52 disposed about
the central opening 46 which provides a gas venting path for
directing inflator gas from the air bag cushion 14. The pad
retainer 70 includes an arcuate slot 54 which is aligned with the
first slot 52 to permit inflator gas to flow therethrough and away
from the air bag cushion 14. The base plate 60 also includes an
arcuate slot 66 formed therein proximate the central opening 62.
Arcuate slot 66 aligns with both the first and second slots 52 and
54 to provide the gas venting path for directing inflator gas from
the air bag cushion 14 when slide actuator assembly 30 is in a
retracted position as illustrated in FIG. 2. The slide actuator
assembly 30 is disposed below the first slot 52 of the adapter
plate 40 and the arcuate slot 54 of the pad retainer 70 to permit
the slide actuator assembly 30 to block both first, second, and
third slots 52, 54, 66 upon actuation thereof. In other words, the
first, second, and third slots 52, 54, 66 comprise a vent opening
generally indicated at 80, wherein the vent opening 80 permits
inflator gas to flow from the inflator 12 and away from the air bag
cushion 14. The slide actuator assembly 30 is designed to
completely close vent opening 80 under predetermined deployment
conditions and thereby prevent the inflator gas from flowing away
from the air bag cushion 14 and instead causes the inflator gas to
flow into the air bag cushion 14.
[0019] In the illustrated embodiment, the slide actuator assembly
30 is mounted to the pad retainer 70 and contacts and communicates
with the adapter plate 40. More specifically, the slide actuator
assembly 30 is mounted to a bottom surface of the pad retainer 70
at the outer periphery of the inflator 12. The pad retainer 70
includes a bottom recessed platform 76 formed by an annular
shoulder 78. The recessed platform 76 is sized to receive the
adapter plate 40 and also permits lateral movement of slide
actuator assembly 30 so that the vent opening 80 may be closed
under predetermined deployment conditions and upon actuation of the
slide actuator assembly 30.
[0020] The cushion retainer 18 includes an annular side wall 82 and
an upper horizontal wall 84 that cooperatively define an annular
cavity 90 opening downwardly towards the base plate 60. Annular
side wall 82 includes an outer flange 86 which extends therefrom,
wherein the outer flange 86 includes an upwardly extending lip 88
about its outer periphery. The air bag cushion 14 is secured
between the outer flange 86 and the base plate 60 to retain the air
bag cushion 14 during deployment.
[0021] The air bag cover or pad (not shown) is commonly used in air
bag modules and is designed to fit over the base plate 60, cushion
retainer 18 and the air bag cushion 14 and fastens to the pad
retainer 70. The cover is preferably molded of a plastic material.
The cover overlies the air bag cushion 14 and inflator 12 and
maintains the air bag cushion 14 in a folded condition prior to air
bag deployment.
[0022] The slide actuator assembly 30 includes a pyrotechnic
initiator 90, a liner 92 and a slide 94 disposed within a generally
cylindrical housing 96. The slide 94, preferably formed of metal,
is a generally L-shaped member having horizontal and vertical
portions 98, 100, respectively. The vertical portion 100 of the
slide 94 engages the liner 92 and the horizontal portion 98 rides
along the adapter plate 40 and is adjacent the flange 34 of
inflator 12 during fill deployment conditions, as shown in FIG. 1.
The width of the horizontal portion 98 is sufficient to cover the
vent opening 80 during full deployment of the air bag module
10.
[0023] The liner 92, formed preferably of a polymeric material, is
substantially cylindrical having an inner cavity 102 that opens at
a bottom surface thereof to receive the initiator 90. It will be
appreciated that liner 92 may be formed of a metal or have a metal
insert. The liner 92 includes a slot 104 at one end thereof for
receiving and retaining the horizontal portion 98 of the slide 94.
Leads 106 extending from the initiator 90 extend through an opening
108 at one end of the housing 96 to permit interconnection with the
controller (not shown). The initiator 90 includes a recess for
receiving and snapfitting thereto a connector (not shown) that
interconnects the initiator 90 and the controller. The liner 92 and
the slide 94 are releasably secured within the housing 96 by known
techniques including the use of a pair of opposing spring tabs (not
shown) disposed on the liner 92, wherein the spring tabs engage a
pair of complementary slots (not shown) formed in the housing 96.
The liner 92 may further include a guide tab (not shown) that
extends from a side wall of the liner 92 which slidably engages a
slot disposed at an edge of the housing 96. The guide tab guides
the travel of and prevents rotation of the liner 92 and slide 94
upon firing of the initiator 90 during full deployment of the air
bag cushion 14.
[0024] According to the present invention, upon actuation of
inflator 12, gas pressure is built up in the cushion retainer 18
and more specifically, the gas pressure within annular cavity 90
builds up as inflator gas flows through vent ports 16 of inflator
12 into the annular cavity 90. This pressurized gas within annular
cavity 90 flows through diffuser openings 20 and into the air bag
cushion 14 and also is permitted to flow through vent opening 80
for venting of a portion of the inflator gas away from the air bag
module 10 when vent opening 80 is opened. The degree of reduced
level deployment of the air bag cushion 14 is dependent upon the
volume of the gas directed away from the air bag cushion 14.
Accordingly, the volume of inflator gas vented from the air bag
module 10 is determined in part by the number of diffuser openings
20 and cross-sectional area of the diffuser openings 20 and the
cross-sectional area of the vent opening 80 formed by first,
second, and third slots 52, 54, 66.
[0025] Thus, the ability to variably control the deployment output
of the air bag module 10 of the present invention results from the
control over the amount of inflator gas produced by the inflator 12
and the ratio between the cross-sectional area of the diffuser
openings 20 in relation to the cross-sectional area of vent opening
80 and the timing of the closure of vent opening 80. For example,
for reduced level deployment, the cross-sectional area of vent
opening 80 is increased in relation to the cross-sectional area of
diffuser openings 20. This may be achieved by either reducing the
cross-sectional area of each of the diffuser openings 20 or by
reducing the number of diffuser openings 20 or by increasing the
cross-sectional area of vent opening 80. Conversely, for increased
low level deployment, the cross-sectional area of vent opening 80
is decreased in relation to the cross-sectional area diffuser
openings 20 by decreasing the cross-sectional area of vent opening
80, increasing the diffuser opening cross sectional area or
increase the number of diffuser openings 20 so that a greater
volume of inflator gas is directed toward the air bag cushion 14
and not through vent opening 80. After the inflator gas is produced
by the inflator 12, the inflator gas is forced from annular cavity
90 by a pressure build up in the annular cavity 90. The inflator
gas produced by the inflator 12 is produced at a rate greater than
the fluid flow rate of the inflator gas through the diffuser
openings 20 due to the number of diffuser openings 20 formed in the
cushion retainer 18 and/or the cross-sectional area of the diffuser
openings 20 and therefore the gas within the annular cavity 90
becomes pressurized and is controllably vented through vent opening
80 during reduced level deployment conditions. By controlling the
cross-sectional area of vent opening 80, the amount of inflator gas
which is permitted to flow away from the air bag cushion 14 and the
rate at which the inflator gas flows are likewise controlled. One
of skill in the art would appreciate that the cross-sectional area
of diffuser openings 20 and vent opening 80 may be varied by
changing the shape or size of these openings.
[0026] In other words, the diffuser openings 20 have a first
cross-sectional area and the vent opening 80 has a second
cross-sectional area. According to the present invention, the
deployment performance of the air bag module 10 is variable because
the ratio actually comprises a selectable ratio and is tunable
depending upon the desired deployment performance. First, the ratio
is selectable because the air bag module 10 may be designed having
predetermined cross-sectional areas with respect to the diffuser
openings 20 and vent opening 80 and second, vent opening 80 may be
left open, closed or closed at a time after the inflator gas begins
to flow but before the inflator 12 is finished generating or
releasing gas. For example, when vent opening 80 is closed none of
the gas flows away from the air bag cushion 14 but instead the
inflator gas flows into the air bag cushion 14 through the diffuser
openings 20. When vent opening 80 is open, the precise amount of
inflator gas which flows to the air bag cushion 14 and the amount
which flows away from the air bag cushion through the vent opening
80 is controlled by selecting the desired ratio between the
cross-sectional area of diffuser openings 20 and the
cross-sectional area of vent opening 80. For example, when the
ratio is about 10:1, in that the cross-sectional area of the
diffuser openings 20 is ten (10) times greater than the
cross-sectional area of vent opening 80, approximately 70% of the
inflator gas flows to the air bag cushion 14, while the remaining
portion flows through vent opening 80. This results in less than
full level deployment of the air bag cushion 14. When the ratio is
varied to about 1:3, only approximately 45% of the inflator gas
flows into the air bag cushion 14 because the cross-sectional area
of the vent opening 80 is now three (3) times greater than the
cross-sectional area of the diffuser openings 20. At a ratio of
about 2:3, approximately 51% of the inflator gas flows into the air
bag cushion 14. Accordingly, by carefully controlling and selecting
the ratio, variable inflator output is achieved.
[0027] Referring now to FIGS. 3 and 4 in which a second embodiment
of an air bag module is illustrated and generally indicated at 10'.
In this embodiment, slide actuator assembly 30 is replaced with a
stopper mechanism 200. Stopper mechanism 200 is pyrotechnically
actuated to either open or close vent opening 80. As shown in FIG.
3, stopper mechanism 200 is in a closed position and the inflator
gas is prevented from flowing through vent opening 80 away from the
air bag cushion 14 resulting in full level deployment. Similar to
slide actuator assembly 30, the stopper mechanism 200 includes a
pyrotechnic initiator 202, a liner 204, and a stopper 206 disposed
within a generally cylindrical housing 208. Stopper 206 has a base
portion 210 which acts to plug vent opening 80 when pyrotechnic
initiator 202 is actuated and a generally L-shaped member 212 which
connects with base portion 210 and extends downwardly therefrom and
seats against an annular liner shell 213 disposed within liner 204.
L-shaped member 212 is preferably integrally formed with the base
portion 210 and in the exemplary embodiment, L-shaped member 212 is
secured to annular liner shell 213 so that actuation of pyrotechnic
initiator 202 causes liner 204, annular liner shell 213 and stopper
206 to travel within housing 208 in a direction toward vent opening
80.
[0028] Base portion 210 includes a neck 214 and an annular shoulder
216 intermediate the L-shaped member 212 and the neck 214. Annular
shoulder 216 in part defines an annular flange 220 which as a
diameter greater than the diameter of the remaining portions of
base portion 210. The diameter of vent opening 80 is likewise less
than the diameter of annular flange 220. Because at least the
annular flange 220 and preferably the base portion 210 is formed of
a sufficiently resilient material, stopper 206 intimately fits
within the vent opening 80 and once annular flange 220 clears the
walls defining vent opening 80, it radially flexes outwardly so
that the annular flange 220 seats against an upper surface of the
annular base plate 60 and prevents fluid communication between the
annular cavity 90 and the outside of the air bag module 10 through
the vent opening 80.
[0029] The liner 204 is substantially cylindrical and includes an
inner cavity 230 that opens at a bottom surface thereof to receive
the pyrotechnic initiator 202. The liner 204 includes a slot 232 at
an upper end thereof for receiving and retaining the L-shaped
member 212. Leads 234 extending from the pyrotechnic initiator 202
extend through an opening 238 at one end of the housing 208 to
permit interconnection with the controller. As previously discussed
with reference to slide actuator assembly 30, liner 204 and annular
liner shell 213 along with stopper 206 are releasedly secured
within the housing 208.
[0030] Upon actuation of the pyrotechnic initiator 202, the liner
204 including the annular liner shell 213 and the L-shaped member
212 of the stopper 206 are driven within the housing 208 toward the
vent opening 80 causing the closure of the vent opening 80. Similar
to the first embodiment, shown in FIGS. 1 and 2, stopper mechanism
200 may be actuated simultaneously with the pyrotechnic initiator
of inflator 12 or may be delayed for a period of time before
stopper mechanism 200 is actuated subsequent to the pyrotechnic
initiator of the inflator 12. FIG. 3 illustrates stopper mechanism
200 in a full level deployment position where inflator gas is
prevented from flowing away from the air bag cushion 14 and all of
the inflator gas is directed into the air bag cushion 14. FIG. 4
illustrates stopper mechanism 200 in a reduced level deployment
position where vent opening 80 is open and inflator gas is
permitted to flow from the annular cavity 90 to the outside of the
air bag module 10 by flowing through the vent opening 80.
[0031] Referring to FIGS. 1-2, in the operation of the air bag
module 10, the default or initial position of the slide 94 may be
disposed in the retracted position shown in FIG. 2 wherein the vent
opening 80 is open to permit gas flow from the inflator 12 to be
directed away from the air bag cushion 14. Likewise in air bag
module 10' of FIGS. 3 and 4, the default position of stopper 206
may be disposed in the retracted position shown in FIG. 4. Upon
actuation of the air bag module 10 under full level deployment, as
shown in FIG. 1, the controller actuates the pyrotechnic initiator
of the inflator 12 to ignite the pyrotechnic material to generate
heated gas that discharges from the vent ports 16 of the inflator
12. Simultaneously or after a delay interval, the controller fires
the pyrotechnic initiator 90 of the slide actuator assembly 30
which propels the liner and slide 94 in a first direction toward
the inflator 12, overcoming the retention force of the spring tabs
of the liner. The flange 34 provides a stop for the travel of the
slide to properly position the slide 94 over the vent opening 80
and forces all the discharged gas from the inflator 12 along a
first fluid flow path 120 into the air bag cushion 14. In other
words, all of the discharged gas flows through vent ports 16 of the
inflator 12 and through the diffuser openings 20 of the cushion
retainer 18 and into the air bag cushion 14 for inflation thereof.
The recessed platform 76 formed in the pad retainer 70 is designed
to accommodate slide 94 and more specifically the horizontal
portion 98 travels within the recessed platform 76 so that the
horizontal portion 98 lies flush against the adapter plate 40 and
slidably travels thereacross during actuation of slide actuator
assembly 30. In the exemplary and illustrated embodiment, the slide
94 includes a bent portion 95 between the horizontal and vertical
portions 98, 100, respectively. Bent portion 95 is a generally
S-shaped segment of the slide 94 and is designed to permit slide 94
to extend from the housing 96 so that the horizontal portion 98
lies flush against the adapter plate 40 and selectively restrict or
block the vent opening 80.
[0032] Upon actuation of the air bag module 10 under reduced level
deployment conditions, the controller does not fire the pyrotechnic
initiator 90 which maintains the slide 94 in the initial position
as shown in FIG. 2 preventing the slide from restricting the vent
opening 80. For air bag module 10', pyrotechnic initiator 202 is
not fired. The vent opening 80, therefore, provides a secondary
fluid flow path 140 (FIGS. 2 and 4) for directing a predetermined
amount of gas away from the air bag cushion 14 and thereby inflates
the air bag cushion 14 at a reduced deployment level. Under these
conditions, only a portion of the inflator gas flows through
diffuser openings 20 from the annular cavity 90 to inflate the air
bag cushion 14, while the remaining inflator gas flows away from
the air bag cushion 14 through the vent opening 80 and thereby
exits the air bag module 10. In other words, the inflator gas flows
both according to the first fluid flow path 120 and the secondary
fluid flow path 140 in both the exemplary embodiments illustrated
in FIGS. 1-4.
[0033] For intermediate level deployment conditions, the controller
is designed so that the pyrotechnic initiator 90 is fired after a
predetermined time interval has passed. More specifically, the
level of reduced deployment, as well as the level of full
deployment, may be varied by providing a time delay between the
firing of the initiator of the inflator 12 and the firing of the
pyrotechnic initiator 90 of the slide actuator assembly 30. For
example, the reduced level of deployment may be increased by firing
the pyrotechnic initiator 90 of the slide actuator assembly 30 a
predetermined time period after firing the initiator of the
inflator 12, which directs the inflator gas away from the air bag
cushion 14 for a shorter period of time.
[0034] One of skill in the art will further appreciate that the
default position of the slide 94 may be in the restricted position
as shown in FIG. 1, wherein the pyrotechnic initiator 90 of the
slide actuator assembly 30 is not ignited under full level
deployment conditions. During reduced level deployment conditions,
the pyrotechnic initiator is ignited to move the slide 94 in a
second direction away from the inflator 12 to the open,
unrestricted position shown in FIG. 2.
[0035] While the air bag module 10 was described as having a
separate base plate 60 and cushion retainer 18, one will appreciate
that the cushion retainer 18 may be combined with the base plate 60
to form a single integral plate having annular cavity 90 and
diffuser openings 20 of the cushion retainer 18. It being
understood that the above-discussed alternative embodiments and
modifications to air bag module 10 are equally applicable to air
bag module 10'.
[0036] The present invention overcomes the deficiencies of the
prior art and offers a more versatile inflator by permitting
control over the moles of gas sent into the air bag cushion by
varying the ratio between the cross-sectional area of diffuser
openings 20 and vent opening 80 so that a desired and predetermined
amount of inflator gas is directed into the air bag cushion 14 for
deployment thereof.
[0037] 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. 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 claims.
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