Land vehicles – Wheeled – Attachment
Reexamination Certificate
2002-12-09
2004-05-25
Dickson, Paul N. (Department: 3616)
Land vehicles
Wheeled
Attachment
C102S530000
Reexamination Certificate
active
06739621
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to the ignition of combustible materials and, more particularly, to ignition of gas generant materials such as used in inflator devices used for the inflation of inflatable restraint airbag cushions.
It is well known to protect a vehicle occupant using a cushion or bag, e.g., an “airbag,” that is inflated or expanded with gas when the vehicle encounters sudden deceleration, such as in a collision. In such systems, the airbag cushion is normally housed in an uninflated and folded condition to minimize space requirements. Upon actuation of the system, the cushion begins being inflated in a matter of no more than a few milliseconds with gas produced or supplied by a device commonly referred to as an “inflator.”
Many types of inflator devices have been disclosed in the art for use in the inflating of one or more inflatable restraint system airbag cushions. Many prior art inflator devices include solid form gas generant materials which are burned to produce or form gas used in the inflation of an associated airbag cushion.
Such inflator devices tend to involve rather complex ignition processes. For example, it is relatively common to employ an electrically initiated squib to ignite a separate charge of an igniter composition. The products of such ignition are then used to ignite the gas generant material. In practice, the ignition process of many various prior inflator devices require such a separate igniter charge because the squib does not itself generally supply sufficient hot gas, condensed phase particles or other ignition products to heat the gas generant material to result in the reaction of the material such as to result in desired gas generation.
FIG. 1
illustrates an inflator device or assembly generally designated by the reference numeral
10
and such as is known in the prior art. The inflator assembly
10
has a generally cylindrical external outline and includes a housing construction
12
such as formed of two structural components, i.e., a lower shell or base portion
14
and an upper shell or diffuser cap portion
16
, such as may desirably be made of steel and appropriately joined or fastened together such as by application of an inertia welding operation. The housing
12
is illustrated in the general form of a flattened, disk-shaped circular cylinder typically or generally having a length to diameter ratio of about 0.5 or less. It will be appreciated that such a sized and shaped housing may most conveniently correspond to the shape of the vehicle steering wheel and can therefore facilitate assembly in an aesthetically pleasing manner.
The diffuser cap portion
16
is in the general form of an inverted bowl and includes a top wall
18
and a cylindrical sidewall
20
. The sidewall
20
includes a plurality of spaced, preferably, generally uniformly spaced gas exit ports
22
.
The base portion
14
includes a mounting opening
24
, the use of which will be discussed in greater detail below. The base portion
14
also includes a peripheral bracket
28
that extends radially outward from the housing
12
and serves to form an interface attachment which is used to attach the inflator assembly
10
to a vehicle, the occupants of which are to be protected from injury such as may result from the impact of a collision.
The housing
12
is configured to define a generally cylindrical chamber
30
. The chamber
30
contains or houses a supply of a gas generant material
32
, such as composed of a pyrotechnic, such as known in the art, in a desired selected form. In
FIG. 1
, the gas generant
32
is shown as contained in the chamber
30
in a tablet form but other forms, such as known in the art may be used. Surrounding the gas generant material
32
is a filter assembly
34
such as includes a cooling screen or filter such as formed of multiple layers or wraps of metal screen.
The inflator assembly
10
also includes a retainer assembly
36
such as composed of a retainer
38
and annular-shaped diffuser and base damper pads,
40
and
42
, respectively, and such as serving as construction expedients. For example, the inclusion of such a retainer assembly or specific components thereof may be useful and desired to retain the inflator assembly components in proper relative arrangement, prevent undesired gas flow passage through the assembly and/or minimize or avoid undesired contact of the gas generant within the assembly
10
such as may create undesired rattle of noise should the assembly be subjected to certain vibrations or other movements or forces. In practice, such damper pad elements are commonly composed or fabricated of a glass fiber material or the like.
Surrounding the filter
34
and generally adjacent the inner surface of the sidewall
20
is an adhesive-backed foil seal
44
which preferably hermetically seals the gas generant material
32
within the inflator
10
, thereby protecting the gas generant material from possibly damaging ambient conditions, such as including moisture.
An igniter assembly, generally designated by the reference numeral
48
, is mounted to the housing
12
in a location within the chamber
30
via the mounting opening
24
. The igniter assembly
48
may take the form of a known pyrotechnic initiator device such as includes, as are known in the art, an igniter cup
50
having an interior
51
wherein is housed an igniter material
52
, an igniter device or squib
54
, and a squib adapter or holder
56
whereby the igniter assembly
48
is mounted to or mated with the housing
12
. As shown, the igniter cup
50
and associated components of the igniter assembly
48
are inserted or fitted into or through an igniter tube
58
. The igniter tube
58
can be formed of a gas-impermeable material, e.g., a metal such as plain carbon steel, and includes a plurality of spaced apart exit orifices
60
wherethrough products of ignition can be passed through and directed into contact with the gas generant material
32
to effect ignition and reaction thereof.
When actuated, the squib
54
causes ignition of the igniter material
52
which customarily results in an increase in pressure within the cup interior
51
with the subsequent predetermined rupturing or opening of the igniter cup
50
to permit passage, through the exit orifices
60
, of ignition products produced by the combustion of the igniter material
52
. With such passage, the ignition products are put into contact with the gas generant material
32
contained within the inflator chamber
30
such as to result in the ignition and reaction of the gas generant material
32
. The gas generant material thus reacts to produce gas. The gas so produced passes through the filter
34
, rupturing the foil seal
44
and passing through the gas exit ports
22
and out from the inflator assembly
10
into an associated airbag cushion (not shown). As will be appreciated, the contact of ignition products with the gas generant material can appropriately be, either or both, thermal or physical in nature.
In practice, the igniter assembly
48
can be formed by placing the igniter cup
50
containing the igniter material
52
over the igniter device/squib
54
and the holder
56
. The igniter assembly
48
can be desirably placed at the mounting opening
24
, such as with the igniter tube
58
in press fit relationship therewith, and joined to the housing
12
such as by welding the holder
56
to the base portion
14
at the mounting opening
24
.
Such igniter charges have also been used in various dual stage or adaptive inflator assemblies. For example,
FIG. 2
illustrates a dual stage or adaptive output inflator device or assembly generally designated by the reference numeral
210
, such as generally disclosed in commonly assigned, co-pending U.S. patent application Ser. No. 09/465,082, the disclosure of which is hereby incorporated by reference. The inflator assembly
210
has various features in common with the inflator assembly
10
, described above. In particular, the inflator assembly
210
has a generally cylindrical external outl
Hammer Steve
Hess Gregg
Kenney Steven B.
Mendenhall Ivan V.
Parkinson David W.
Autoliv ASP Inc.
Brown Sally J.
Dickson Paul N.
Erickson James D.
To Toan C
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