Note: Descriptions are shown in the official language in which they were submitted.
2118~5
PATENT
INFLATOR ASSEMBLY
Background of the Invention
The present invention relates to an inflator assembly
for inflating a vehicle occupant restraint, such as an air
bag.
Known inflator assemblies use a combination of stored
gas and gas generated by ignition of gas generating
material to inflate an air bag. These inflator assemblies
include an igniter which is activated to ignite the gas
generating material. Upon ignition of the gas generating
material, the generated gas provides fluid pressure which
ruptures a disk to release the stored gas from the inflator
assembly for flow to an air bag. The gas generated by
ignition of the gas generating material can then also flow
from the inflator assembly to the air bag. Inflator
assemblies constructed in this manner are disclosed in U.S.
Patents Nos. 3,806,153 and 3,895,821.
SummarY of the Invention
The present invention relates to an inflator assembly
for inflating a vehicle occupant restraint, such as an air
bag. 21 i 8476
The invention provides an apparatus for use in inflating a vehicle
occupant restraint, said apparatus comprising: a container for holding a supply of
gas; surface means for defining a gas discharge opening for directing gas from
said container; a quantity of pressure producing material, said quantity of pressure
producing material being ignitable to produce pressure; said container having a
closure member blocking said gas discharge opening and at least partially
enclosing said quantity of pressure producing material, said closure member
including a breakable portion adjacent to said discharge opening, a side wall
10 portion extending from said breakable portion and at least partially enclosing said
quantity of pressure producing material, and an end wall portion connected with
said side wall portion of said closure member; and igniter means for igniting said
quantity of pressure producing material to create pressure against said end wall
portion of said closure member to break said breakable end portion of said closure
member and to move at least said side wall portion and said end wall portion of
said closure member away from said discharge opening to enable gas to flow
through said discharge opening toward the vehicle occupant restraint.
The invention also provides an apparatus for use in inflating a vehicle
occupant restraint, said apparatus comprising: a container for holding a stored
20 supply of gas, said container including a longitudinally extending side wall, and an
end wall connected with one end of said side wall; a housing having a base
section and a main section which extend from said end wall; a quantity of pressure
producing material disposed in said main section of said housing, said quantity of
pressure producing material being ignitable to produce pressure; said end wall
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21 1 8476
having surface means for defining discharge openings for directing gas from saidcontainer; a closure member which extends between said main section of said
housing and said end wall to block a flow of gas from said container through said
discharge openings, said closure member being connected with said end wall at a
location which is spaced from said base section, said closure member having a
frangible section which extends around said base section and is breakable to
enable gas to flow from said container through said discharge openings; and
igniter means for igniting said quantity of pressure producing material to create
pressure and effect a breaking of said frangible section of said closure member to
enable gas to flow from said container through said discharge openings.
The invention also provides an apparatus for use in inflating a vehicle
occupant restraint, said apparatus comprising: a container for holding a stored
supply of gas; a body of gas generating material, said body of gas generating
material including an end surface and a side surface extending from said end
surface; a housing enclosing said body of gas generating material, said housing
including a side wall which extends along the side surface of said body of gas
generating material and an end wall which is connected with said side wall, saidend wall having a plurality of passages through which gas from said body of gas
generating material is conducted upon ignition of said body of gas generating
material, said end wall having a plurality of projections which extend between the
side surface of said body of gas generating material and said side wall of said
housing and which engage the side surface of said body of gas generating
material to locate said body of gas generating material and said end wall relative
to each other; and igniter means for igniting said body of gas generating material
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Zl ~ 8476
to create gas which flows through the passages in said end wall of said housing to
augment the stored supply of gas in said container.
The invention also provides an apparatus for use in inflating a vehicle
occupant restraint, said apparatus comprising: a container for holding a supply of
gas under pressure, said container including a longitudinally extending side wall
and an end wall connected with one end of said side wall, said end wall including
surface means for defining an array of passages which extend through said end
wall; a housing connected with and extending through said end wall of said
container at a generally central location within the array of passages; a body of
10 gas generating material disposed in said housing, said body of gas generating
material being ignitable to produce gas; igniter means disposed in said housing for
igniting said body of gas generating material; and diffuser means for directing a
flow of gas from the passages in said first end wall, said diffuser means including
an end wall connected to said housing, said diffuser means including a side wall
connected to said end wall of said container outwardly of the array of passages,
said side wall and end wall of said diffuser means cooperating with said end wall
of said container and said housing to form a diffuser chamber which extends
around a portion of said housing and receives gas from open ends of passages in
said array of passages, said end wall of said diffuser means extending from said
20 housing outwardly across the open ends of the passages to deflect gas flow from
the passages toward said side wall of said diffuser means, said side wall of said
diffuser means including a plurality of passages through which gas flows from said
diffuser chamber.
The invention also provides an apparatus for use in inflating a vehicle
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27789-50
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21 1 8476
occupant restraint, said apparatus comprising: a container for holding a supply of
gas under pressure, said container including a longitudinally extending side wall
and an end wall connected with one end of said side wall, and surface means for
defining a plurality of passages which extend through said end wall, said side wall
of said container being fixedly secured to said end wall; a housing connected to a
central portion of said end wall; a body of gas generating material disposed in said
housing, said body of gas generating material being ignitable to produce gas;
closure means connected to said end wall for blocking a flow of gas through said
passages, said closure means being breakable to enable gas to flow through said
10 passages upon ignition of said body of gas generating material; igniter means
disposed in said housing for igniting said body of gas generating material; and
diffuser means connected to said end wall for diffusing a flow of gas from the
passages, said diffuser means having passages for directing a flow of gas from
said diffuser means and in a direction transverse to the direction of flow of gas
through said plurality of passages.
Upon activation of the igniter, the pressure producing material is
ignited and produces gas pressure. This gas pressure is applied against the
closed end of the cup shaped closure member and breaks a frangible section of
the closure member. Breaking the frangible section of the closure member
20 disconnects the closure member from the container. The gas pressure resulting
from ignition of the quantity of pressure producing material moves the closure
member away from the housing for the gas generating material. The gas from the
quantity of pressure producing material mixes with and heats the stored gas. The
stored
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gas and the gas from the quantity of pressure producing
material flow through the discharge opening into the
diffuser. The gas then flows from the diffuser into the
vehicle occupant restraint.
Brief DescriPtion of the Drawinqs
The foregoing and other objects and features of the
present invention will become more apparent to one skilled
in the art upon a consideration of the following
description of the invention and the accompanying drawings
in which:
Fig. 1 is a sectional view of an inflator assembly
constructed in accordance with the present invention;
Fig. 2 is an enlarged fragmentary sectional view of a
portion of the inflator assembly of Fig. l;
, 15 Fig. 3 is an enlarged pictorial illustration of a part
of the inflator assembly of Fig. 1;
Fig. 4 is a sectional view, taken approximately along
the line 4-4 of Fig. 2;
Fig. 5 is a sectional view, taken approximately along
the line 5-5 of Fig. 2;
Fig. 6 is a sectional view, generally similar to Fig.
1, illustrating the relationship between parts of the
inflator assembly of Fig. 1 after the inflator assembly has
been actuated;
Fig. 7 is a fragmentary sectional view of a portion of
a second embodiment of an inflator assembly constructed in
accordance with the present invention;
2118~76
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Fig. 8 is a view taken generally along the line 8-8 of
Fig. 7; and
Fig. 9 is a fragmentary sectional view of a portion of
a third embodiment of an inflator assembly constructed in
accordance with the present invention.
Description of
Embodiments of the Invention
General Description
An inflator assembly 10 (Fig. l) inflates a vehicle
occupant restraint, such as an air bag (not shown). The
inflator assembly 10 includes a generally cylindrical
container 12 having a chamber 16 which holds a supply of
stored gas. The stored gas is preferably 95% argon and 5%
helium. The gas is stored in the container 12 at a
pressure of approximately 2,000 to 3,500 psi. Other gases
! could be stored in the container 12, and the gases could be
stored at different pressures. For example, air or
nitrogen could be stored in the container 12.
A cup shaped closure member 24 blocks gas flow from
the chamber 16 through a plurality of discharge passages
28. The cup shaped closure member 24 has a closed end 24a
and an opposite open end. A quantity of material which
produces pressure when at least partially ignited is
disposed in a housing 22. The quantity of material is
preferably a body 20 of gas generating material which
extends into the cup shaped closure member 24. An igniter
32 IS also disposed within the housing 22.
~'1 1847~
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When an air bag is to be inflated to restrain movement
of an occupant of a vehicle, the igniter 32 is activated to
ignite the body 20 of gas generating material. Ignition of
the body 20 of gas generating material creates gas which
applies pressure against the closed end 24a of the closure
member 24. The gas pressure applied to the closed end 24a
of the closure member 24 breaks the closure member and
moves it away from the discharge passages 28, as shown in
Fig. 6. The stored gas and the gas from the body 20 of gas
generating material then flow from the chamber 16 through
the discharge passages 28 into a diffuser 36. The gas
flows from the diffuser 36 into the air bag to inflate the
air bag which restrains movement of an occupant of a
vehicle in a ]cnown manner.
Cont~iner
The container 12 (Fig. 1) includes a cylindrical one-
piece steel side wall 40. The side wall 40 has a
longitudinal central axis which is coincident with a
longitudinal central axis 42 of the container 12. The
container 10 also includes a one-piece circular steel end
wall 44 which is connected with the right (as viewed in
Fig. 1) end of the side wall 40 at an annular weld 46. A
pressure sensor 48 is mounted on the end wall 44 to sense
the fluid pressure in the chamber 16. A fill passage 52 is
formed in the end wall 44 and is closed by a steel ball 54
which is welded in place. The circular end wall 44 is
211847~
--6--
coa~ial with the side wall 40. The central axis 42 of the
con-tainer 12 extends through the center of the end wall 44.
A circular steel end wall 58 is connected with the
left (as viewed in Fig. 1) end of the side wall 40 by an
annular weld 60. The left end wall 58 is disposed in a
coaxial relationship with the right end wall 44 and the
side wall 40 of the container 12. The end wall 58 has
parallel inner and outer, radially extending side surfaces
62 and 64. Inner side surface 62 is presented toward the
interior of the container 12, while the outer side surface
64 is presented away from the interior of the container.
The weld 60 connects the left (as viewed in Fig. 1) end of
the side wall 40 with the end wall 58 at a location
intermediate the inner ,and outer side surfaces 62 and 64.
The discharge passages 28 are formed in the end wall
58. The discharge passages 28 have cylindrical
configurations with central axes which extend parallel to
the central axis 42 of the container 12. The discharge
passages 28 are arranged in an annular array about the
central axis 42 of the container 12. Although only two
discharge passages 28 are shown in Fig. 1, it should be
understood that there are a plurality of discharge passages
formed in the end wall 58.
An annular metal foil seal 70 is secured to the outer
side surface 64 of the end wall 58 across the ends of
discharge passages 28. The metal foil seal 70 is secured
to the outer side surface 64 of the end wall 58 by a
~ ~847~
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suitable adhesive. The seal 70 blocks the conduction of
moisture from the environment around the inflator assembly
10 through the discharge passages 28.
Housinq
The housing 22 encloses the body 20 of gas generating
material. The housing 22 has a central axis which is
coincident with the central axis 42 of the container 12.
The housing 22 includes a tubular base section 74 (Fig. 2)
which extends through the end wall 58 of the container 12.
The base section 74 is generally circular in transverse
section. An annular, radially extending shoulder 76 on the
outer surface of the base section 74 abuts the inner side
surface 62 of the end wall 58. An annular weld 80 connects
the base section 74 of the housing 22 with the outer side
, 15 surface 64 of the end wall 58.
The base section 74 of the housing 22 has a
cylindrical outer end portion 86 which extends axially
outward, that is, away from the interior of the container
12 and toward the left as viewed in Fig. 2, from the end
20 wall 58. An inner end portion 88 of the base section 74
extends axially inward, that is, toward the interior of the
container 12 and to the right as viewed in Fig. 2, from the
end wall 58. A cylindrical passage 90 extends through the
center of the base section 74. The igniter 32 is located
in the passage 90.
A tubular main section 94 of the housing 22 is formed
as one piece with the base section 74. The main section 94
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of the housing 22 includes a cylindrical side wall 96. The
side wall 96 and base section 74 have central axes which
are coincident with the central axis 42 of the container
12. The cylindrical side wall 96 has a relatively large
S outer diameter. Therefore, the base section 74 flares
radially outwardly to the side wall 96 of the main section
94 of the housing 22.
The main section 94 of the housing 22 has a
cylindrical housing chamber 98 (Fig. 2). The housing
chamber 98 has a central axis which is coincident with the
central axis 42 of the container 12. The housing chamber
98 contains an annular ring 100 of auto-ignition material
adjacent to one end of the body 20 of gas generating
material. An annular c,ushioning ring 102 is disposed
betwPen the ring 100 of auto-ignition material and an
! annular end surface or shoulder 104 on the housing 22.
The cushioning ring 102 rests against the radially
extending shoulder 104, which is formed on the axially
inner end of the base section 74 of the housing 22. The
cushioning ring 102 has a central axis which is coincident
with the central axis 42 of the container 12. The
cushioning ring 102 is formed of a suitable polymeric
material, such as silicone.
The annular ring 100 of auto-ignition material is
disposed in a coaxial relationship with the cushioning ring
102 and the body 20 of gas generating material. The ring
100 of auto-ignition material is preferably a stabilized
~11347~
nitrocellulose composition, such as IMR 4895 which is
commercially available from E. I. DuPont de Nemours & Co.
The auto-ignition material ignites at a temperature of
about 350~F. A flat annular side surface 103 of the ring
100 of auto-ignition material is disposed in abutting
engagement with a flat end surface 105 on the body 20 of
gas generating material. Similarly, a parallel flat
annular side surface 106 on the ring 100 of auto-ignition
material is disposed in abutting engagement with a flat
annular side surface 107 on the cushioning ring 102.
The body 20 of gas generating material has a multi-
lobe cross-sectional configuration (Fig. 5) and extends
from the cushioning ring 102 (Fig. 2) through the housing
chamber 98 to a circular end wall 108 of the housing 22. A
plurality of straight cylindrical passages 110, 112, 114,
' and 116 (Fig. 5) extend between axially opposite ends of
the body 20 of gas generating material (Fig. 2). The
passages 110, 112, 114 and 116 have longitudinal central
axes which are parallel to the central axis 42 of the
container 12.
The body 20 of gas generating material has a
continuous, curved outer side surface 118 (Fig. 5) which
defines and extends around four lobes through which the
passages 110, 112, 114 and 116 extend. Although the body
20 of gas generating material has been illustrated in Fig.
5 as having four lobes and passages 110, 112, 114 and 116,
it is contemplated that the body of gas generating material
~118~7~ ~
--10--
could be formed with a different configuration if desired.
The body 20 of gas generating material is a pyrotechnic
material which may have many different compositions. For
example, the body 20 of gas generating material may have
the composition disclosed in U.S. Patent No. 5,131,680.
The end wall 108 (Figs. 2, 3 and 4) of the housing 22
is a powdered metal part, but may be made from an alloy
steel. The end wall 108 has a flat circular, radially
extending inner side surface 124 which abuttingly engages
one end of the body 20 of gas generating material (Fig. 2).
The end wall 108 also has a flat circular, radially
extending outer side surface 126 which extends parallel to
the inner side surface 124. An annular crimp or rim 130 at
the right (as viewed in;Fig. 2) end of the cylindrical
housing side wall 96 engages the outer side surface 126 of
' the end wall 108 to hold the end wall in place in the
housing 22. A plurality of passages are provided in the
end wall 108 to conduc~ gas which is created upon ignition
of the body 20 of gas generating material. Specifically,
the end wall 108 has four cylindrical main passages 134,
136, 138 and 140 (Figs. 3 and 4) which extend through the
end wall 108 and are aligned with the passages 110, 112,
114 and 116 (Fig. 5) in the body 20 of gas generating
material.
A plurality of secondary passages 144, 146, 148 and
150 (Figs. 3 and 4) also extend through the end wall 108.
The main passages 134, 136, 138 and 140 through the end
?118~7~
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wall 108 conduct gas from the passages 110, 112, 114 and
116 (Fig. 5) in the body 20 of gas generating material.
The secondary passages 144, 146, 148 and 150 (Figs. 3 and
4) conduct gas from passages formed between the housing 22
and spaces between the lobes in the body 20 of gas
generating material (Fig. 5).
Two diametrically opposed projections 154 and 156
extend from the inner side surface 124 of the end wall 108
(Fig. 3). The projections 154 and 156 engage the outer
side surface 118 of the body 20 of gas generating material
between adjacent lobes (Fig. 5). Engagement of the
projections 154 and 156 with the body 20 of gas generating
material positions the end wall 108 and body of gas
generating material relative to each other so that the main
passages 134, 136, 138 and 140 (Fig. 3) are axially aligned
with the passages 110, 112, 114 and 116 (Fig. 5) through
the body 20 of gas generating material. The secondary
openings 146 and 150 extend through the projections 154 and
156.
Closure Member
The closure member 24 (Fig. 2) blocks the discharge
passages 28 and encloses the main section 94 of the housing
22. The closure member 24, as discussed above, has a
generally cup shaped configuration and is formed as one
piece of a suitable material, such as low carbon steel or
annealed stainless steel. The closure member 24 has a
7 6
-12-
central axis which is coincident with the central axis 42
of the container 12.
The closure member 24 includes a skirt section 162
which is connected to the flat circular inner side surface
62 o~ the end wall 58 (Fig. 2). The closure member 24 has
a cylindrical side wall 164 which is connected to and is
coaxial with the skirt section 162. The side wall 164
encloses the main section 94 of the housing 22 and the body
20 of gas generating material. An imperfora~e circular end
wall 166 of the closure member 24 is connected with the
right (as viewed in Fig. 2) end portion of the side wall
164 and closes the end 24a of the cup shaped closure
member. The end wall 166 extends across the right (as
viewed in Fig. 2) end of the housing 22.
The skirt section 162 has a side wall 170 with a
configuration which is a frustrum of a cone. An annular
flange 172 extends radially outwardly from the left (as
viewed in Fig. 2) end of the side wall 170 and is welded to
the end wall 58. The annular flange 172 circumscribes the
annular array of inlet openings to the discharge passages
28. The annular flange 172 is disposed in a coaxial
relationship with the annular array of discharge passages
28.
The side wall 170 of the skirt section 162 extends
from the main section 94 of the housing 22 to the inner
side surface 62 of the end wall 58. In the embodiment of
the invention illustrated in Fig. 2, the cylindrical main
2118~7~
! - 13-
section 94 of the housing 22 has a outer surface which is
located radially inward of the longitudinal axes of the
individual discharge passages 28. Therefore, the skirt
section 162 flares axially away and radially outwardly from
the main section 94 of the housing 22 toward the end wall
58. However, it is contemplated that the main section 94
of the housing 22 could be formed with a somewhat larger
diameter so that the skirt section 162 could be cylindrical
and still circumscribe the annular array of discharge
passages 28.
An annular frangible section 176 (Fig. 2) of reduced
thickness is formed in the skirt section 162. The
frangible section 176 is breakable under the influence of
tension forces transmit,ted from the end wall 166 of the cup
shaped closure member 24 upon ignition of the body 20 of
' gas yenerating material. The frangible section 176 is
coaxial with the central axis 42 of the container 12 and
extends around the base section 74 of the housing 22.
The skirt section 162 (Fig. 2) has an inner side
surface 180 which cooperates with the inner side surface 62
on the end wall 58 and an outer side surface of the base
section 74 to form an annular manifold chamber 182. The
manifold chamber 182 extends around the base section 74 of
the housing 22 and has a central axis which is coincident
with the central axis 42 of the container 12. The
discharge passages 28 in the end wall 58 have circular
inner ends which open to the manifold chamber 182.
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Prior to breaking of the frangible section 176 of the
skirt section 162, the manifold chamber 182 is isolated
from the stored gas in the chamber 16. Thus, the fluid
pressure in the manifold chamber 182, prior to breaking of
the frangible section 176, will be approximately
atmospheric pressure while the stored gas in the chamber 16
will be at a pressure of, for example, 2,000 to 3,500 psi.
The tubular side wall 164 (Fig. 2) of the closure
member 24 has a cylindrical inner side surface 186 which is
disposed in engagement with a cylindrical outer side
surface of the main section 94 of the housing 22. The
inner side surface 186 of the side wall 164 is freely
slidable along the outside of the housing 22 under the
influence of gas pressu~e applied against the end wall 166
after ignition of the body 20 of gas generating material
and breaking of the frangible section 176 of the closure
member 24.
Iqniter
The igniter 32 is located in the passage 90 (Fig. 2)
which extends through the base section 74 of the housing
22. The igniter 32 has a cylindrical configuration. The
igniter 32 is axially aligned with the left (as viewed in
Fig. 2) end of the body 20 of gas generating material.
The igniter 32 is actuatable to ignite the body 20 of
gas generating material. The igniter 22 has a metal casing
which is connected with the outer or left (as viewed in
Fig. 2) end of the base section 74 of the housing 22 by an
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annular weld 194. The igniter 32 includes a pyrotechnic
charge which may be zirconium potassium perchlorate or
BKNO3 or, if desired, a different chemical composition.
The igniter 32 is connected with a sensor assembly
(not shown) which detects vehicle deceleration. If the
sensor assembly detects excessive vehicle deceleration, the
sensor assembly completes an electrical circuit with an
energy source to activate the igniter assembly 32 to effect
igni~ion of the body 20 of gas generating material.
A one-piece seal cup 200 (Fig. 2) is disposed in the
passage 90 and receives the igniter 32 to block the
conduction of moisture from the environment around the
inflator assembly 10 to the body 20 of gas generating
material. The seal cupiis formed as a single piece of
metal and has a thickness of between 0.20 and 0.30
' millimeters. The seal cup 200 has an annular flangè 202
which is connected with the outer or left (as viewed in
Fig. 2) end of the base section 74 by the weld 194. A
plurality of score lines (not shown) extend diametrically
across the right (as viewed in Fig. 2) end wall 204 of the
seal cup 200. The score lines have a depth of
approximately 0.10 to 0.05 millimeters. The score lines
weaken the seal cup 20 so that it is easily ruptured upon
activation of the igniter 32.
Diffuser
The diffuser 36 is formed as one piece of steel. The
diffuser 36 has a circular end wall 208 (Fig. 2) which
4 7 6
-16-
extends radially outwardly from the outer end portion 86 of
the base section 74 of the housing 22. The diffuser end
wall 208 is connected to the base section 74 of the housing
22 by an annular weld 210. The end wall 208 of the
diffuser 36 has a central axis which is coincident with the
central axis 42 of the container 12.
The end wall 208 has a flat circular, radially
extending inner side surface 212. The surface 212 on the
end wall 208 extends parallel to and is spaced from the
flat circular outer side surface 64 on the end wall 58.
A cylindrical side wall 216 (Fig. 2) of the diffuser
36 is formed as one piece with the end wall 208 and extends
axially from the outer periphery of the end wall. The
outer diameter of the cylindrical side wall 216 of the
diffuser 36 is the same as the diameter of the outer side
' surface 64 on the end wall 58. The cylindrical side wall
216 of the diffuser 36 is welded to the outer side surface
64 of the container end wall 58.
An annular array of radially extending cylindrical
passages 220 is formed in the side wall 216 of the diffuser
36. The combined flow area of the passages 220 is larger
than the combined flow area of the passages 28 in the end
wall 58. The radially extending passages 220 are connected
in fluid communication with an annular diffuser chamber 222
which is defined by the diffuser 36, the container end wall
58, and the base section 74 of the housing 22. The
diffuser chamber 222 extends around the outer end portion
4 7 ~
86 of the base section 74 of the housing 22. The diffuser
passages 220 are also connected in fluid communication with
the inside of an air bag (not shown).
The body 20 of gas generating material, housing 22,
closure member 24, igniter 32 and diffuser 36 are all
connected with the end wall 58 of the container 12. By
connecting the housing 22, closure member 24 and diffuser
36 to the end wall 58, these components of the inflator
assembly 10 can be mounted as a unit on the side wall 40 of
the container. The igniter 32 can be connected to the
housing 22 after the end wall 58, housing 22, closure
member 24 and diffuser 36 have been connected as a unit
with the side wall 40 of the container 12.
Oper~tion
, 15 Upon the occurrence of sudden vehicle deceleration,
the deceleration sensor (not shown) completes an electrical
circuit to activate the igniter 32 (Fig. 2) in a known
manner. This results in ignition of a pyrotechnic charge
in the igniter 32. Burning of the pyrotechnic charge in
the igniter 32 generates gas which ruptures the relatively
thin seal cup 200.
Rupturing the seal cup 200 enables hot gases to flow
through the passage 90 in the base section 74 of the
housing 22. The hot gases engage the left (as viewed in
Fig. 2) end portion of the body 20 of gas generating
material. The hot gases ignite the body 20 of gas
generating material.
~11847S
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Upon ignition of the body 20 of gas generating
material, gas is conducted through the end wall 108 of the
housing 22. This gas applies pressure against the end wall
166 of the closure member 24. The pressure applied against
S the end wall 166 of the closure member 24 results in the
transmission of tensile forces through the side wall 164 of
the closure member to the skirt section 162 of the closure
member. These tensile forces are effective to break the
frangible section 176 (Fig. 2) of the skirt section 162.
Upon breaking of the frangible section 176 of the
skirt section 162, the fluid pressure applied by the gas
from the burning body 20 of gas generating material moves
the closure member 24 away from the end wall 58 of the
container 12 toward thejopposite end wall 44 (see Fig. 6).
Thus, the fluid pressure applied against the end wall 166
(Fig. 2) of the closure member 24 moves the closure member
toward the right (as viewed in Fig. 2). This movement of
the closure member 24 is initially guided by sliding
movement of the side wall 164 of the closure member along
the side wall 96 of the housing 22. The closure member 24
then separates from the housing 22 and comes to rest
adjacent to the end wall 44 of the container 12 (Fig. 6).
As soon as the frangible section 176 in the skirt
section 162 (Fig. 2) breaks, the stored gas in the chamber
16 flows into the annular manifold chamber 182. The gas
pressure transmitted from the manifold chamber 182 through
the discharge passages 28 ruptures the seal 70 (Figs. 2 and
2~ ~ ~4 '76
--19--
6). Gas then flows from the chamber 16 through the
discharge openings 28 into the diffuser chamber 222.
When the gas enters the diffuser chamber 222, it
impinges against the end wall 208 of the diffuser 36. The
end wall 208 of the diffuser 36 directs the gas flow
radially outwardly toward the openings 220 in the side wall
216 of diffuser 36. The gas flows through the openings 220
to the air bag.
The gas created by burning the body 20 of gas
generating material flows into chamber 16. This relatively
hot gas mixes with, heats, and augments the supply of
stored gas in the chamber 16. The combined volume of the
gas stored in the chamber 16 and the gas created by burning
of the body 20 of gas g,enerating material provides the
desired volume of gas to inflate the air bag which is
' connected in fluid coimmunication with the diffuser 36.
In Fig. 6 of the drawings, the igniter 32, the ring
100 of auto-ignition material, and the body 20 of gas
generating material are illustrated in their condition
prior to actuation of the inflator assembly 10. However,
it should be understood that the igniter 32 is destroyed,
and the ring 100 of auto-ignition material and body 20 of
gas generating material are consumed during actuation of
the inflator assembly 10.
Second Embodiment
Figs. 7 and 8 illustrate a second embodiment of the
present invention. In the embodiment of Figs. 7 and 8, a
2118476
-20-
housing 300 encloses a body 302 of gas generating material.
The housing 300 differs from the housing 22 illustrated in
Fig. 2 in that the housing 300 has a cylindrical main
section 304 with a larger outer diameter than the main
S section 94 of the housing 22 of the embodiment of Fig. 2.
A cup shaped closure member 306 (similar to closure
member 24 of the embodiment of Fig. 3) encloses the main
section 304 of the housing 300. Due to the relatively
larqe outer diameter of the main section 304 of the housing
300 (Fig. 7), the closure member 306 has a skirt section
308 which is formed as a continuation of a cylindrical side
wall 310 of the closure member 306. An annular frangible
section 312 is formed in the skirt section 308. The
frangible section 312 is breakable under the influence of
tension forces transmitted from an end wall 314 through the
side wall 310 and through the skirt section 308 of the
closure member 306.
The end wall 314 of the closure member 306 is formed
with a plurality of projections 320 which extend axially
away from the side wall 310 of the closure member 306 and
radially outward from a center of the end wall 314. The
projections 320 increase the structural rigidity of the end
wall 314 of the closure member 306.
In the embodiment of the invention illustrated in Fig.
7, the diffuser 330 has an end wall 332 which is formed as
one piece with a generally cylindrical side wall 334. The
end wall 332 of the diffuser projects axially beyond the
~tl~7~
-21-
hou:;ing 300, toward the left as viewed in Fig. 7, to form a
shield to protect an outer end portion 338 of the housing
300. If the inflator assembly should be dropped, for
example, the outwardly projecting end wall 332 of the
diffuser will help protect the igniter and outer end
portion 338 of the housing against striking the floor or
other object upon which the inflator assembly is dropped.
Also, in the embodiment of the invention illustrated
in Fig. 7, generally oblong passages 340 are formed in the
side wall 334 of the diffuser 330 instead of the circular
openings of the embodiment of Fig. 2.
Third Embodiment
In the embodiment of the invention illustrated in Fig.
9, a cup shaped closure member 400 has the same general
construction and configuration as the closure member 306 of
Fig. 7. The closure member 400 extends around a
cylindrical main section 402 of a housing 404. A frangible
section 408 is formed in a skirt portion 410 of the closure
member 400. The skirt portion 410 and a side wall 414 of
the closure member have approximately the same outer
diameter and thus form a cylinder as in the embodiment of
Fig. 7. The skirt portion 410 has a radial thickness which
is less than the radial thickness of the side wall 414 of
the closure member 400. The reduced thickness of the skirt
portion 410 enables the skirt portion to be deflected
radially inwardly to the position shown in dashed lines in
Fig. 9 upon breaking of the frangible section 408, such as
~118~76
-22-
by a predetermined increase in the gas pressure applied
against an outer side surface of the skirt portion 410.
Thus, the skirt portion 410 is deflected radially inwardly
into an annular manifold chamber 418 and provides a flow
area through which gas flows toward discharge passages 420
formed in an end wall 422.
If, for some reason, such as a temperature increase,
the pressure of the gas stored in the inflator should
become excessive, the fluid pressure of the gas against the
skirt portion 410 of the closure member 400 will cause the
closure member to break at the frangible section 408. The
pressure applied by the gas against the reduced thickness
skirt portion 410 will then deflect the skirt portion
radially inwardly to th,e position shown in dashed lines in
Fig. 9 to provide a flow area to enable the stored gas to
flow through the discharge passages 420.
From the above description of the invention, those
skilled in the art will perceive improvements, changes and
modifications. Such improvements, changes and
modifications within the skill of the art are intended to
be covered by the appended claims.
