Land vehicles – Wheeled – Attachment
Reexamination Certificate
2001-08-17
2003-08-19
Dunn, David R. (Department: 3616)
Land vehicles
Wheeled
Attachment
C102S531000
Reexamination Certificate
active
06607214
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to gas generation and, more particularly, to the indirect ignition of igniter materials such as used in inflator devices used for providing or supplying inflation gas to inflatable passive restraint systems for use in vehicles for restraining the movement of an occupant in the event of a vehicular collision.
It is well known to protect a vehicle occupant by means of safety restraint systems which self-actuate from an undeployed to a deployed state without the need for intervention by the operator, i.e., “passive restraint systems.” Such systems commonly contain or include an inflatable vehicle occupant restraint or element, such as in the form of a cushion or bag, commonly referred to as an “airbag cushion.” In practice, such airbag cushions are typically designed to inflate or expand with gas when the vehicle encounters a sudden deceleration, such as in the event of a collision. Such airbag cushions may desirably deploy into one or more locations within the vehicle between the occupant and certain parts of the vehicle interior, such as the doors, steering wheel, instrument panel or the like, to prevent or avoid the occupant from forcibly striking such parts of the vehicle interior.
Various types or forms of such passive restraint assemblies have been developed or tailored to provide desired vehicle occupant protection such as based on either or both the position or placement of the occupant within the vehicle and the direction or nature of the vehicle collision, for example. In particular, driver side and passenger side inflatable restraint installations have found wide usage for providing protection to drivers and front seat passengers, respectively, in the event of head-on types of vehicular collisions. Driver side and passenger side inflatable restraint installations do not, however, generally provide as great as may be desired protection against vehicular impacts inflicted or imposed from directions other than head-on, i.e., “side impacts.” In view thereof, substantial efforts have been directed to developing inflatable restraint installations having particular effectiveness in the event of a side impact.
Upon deployment, the time period during which an airbag cushion remains pressurized is commonly referred to as “stand-up time.” In practice, driver side and passenger side airbag cushions are typically desirably designed to begin deflating almost instantaneously upon deployment such as to avoid presenting an undesirably hard or ungiving surface to an oppositely situated vehicle occupant. However, airbag cushions which provide substantially longer stand-up times may be required or desired in the event of certain accidents or collisions in order to provide a suitable desired level of occupant protection. For example, one particularly troublesome form of side impact is commonly referred to as a “roll-over.” In a roll-over incident, a vehicle may undergo a partial or complete roll-over or may undergo multiple roll-overs. As will be appreciated by those skilled in the art, roll-over accidents can be particularly demanding on inflatable restraint systems. In particular, an airbag cushion designed to provide occupant protection in the event of a vehicle roll-over may be required or desired to remain pressurized for an extended or prolonged period of time, as compared to usual or typical driver side and passenger side airbag installations. For example, a roll-over protection side impact airbag cushion desirably remains pressurized or provides a stand-up time as long as about 5 seconds and, in some applications, a stand-up time of nearly 7 seconds.
One particularly effective form of side impact inflatable restraint is the subject of HÅland et al., U.S. Pat. No. 5,788,270, issued Aug. 4, 1998, the disclosure of which patent is hereby incorporated by reference herein in its entirety and made a part hereof. Inflatable elements, such as disclosed in HÅland et al., U.S. Pat. No. 5,788,270, may desirably include an inflatable portion formed from two layers of fabric with the front layer and the back layer of the fabric woven together at selected points. In particular embodiments, such selected points are arranged in vertically extending columns and serve to divide the inflatable part into a plurality of vertical parallel chambers. The spaces between the selected points permit internal venting between adjacent chambers of the inflatable element. Particular such inflatable devices/elements, such as utilized in applications to provide protection over an extended area and having a generally planar form, are frequently referred to as “inflatable curtains.”
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. Known types of inflator devices include inflators known as “blow down” inflators and “reverse flow” inflators. In a blow down inflation system, a pyrotechnic or other selected material is commonly burned to create a build-up of pressure within a compressed gas storage chamber such as to result in the rupture or release of inflation gas therefrom when the internal pressure reaches a predetermined level or range. Thus, in blow down inflator devices, the opening or rupture of a seal, burst disk or the like within the inflator typically results or produces a flow of heated or elevated temperature inflation gas from the device and into an associated airbag cushion. While blow down inflation systems can desirably be of relatively lower cost and complexity, such systems can result in the delivery of inflation gas to an associated airbag cushion at a higher temperature, pressure and/or mass flow rate than may otherwise be desired.
In “reverse flow” inflator devices, the actuating initiator and the openings wherethough the inflation gas exits from the inflator device are typically at or along the same end or side of the inflator device. Thus, in typical reverse flow inflators, the initial inflation gas exiting from the inflator device and into an associated airbag cushion is relatively cool and is later followed by heated or elevated temperature inflation gas. Consequently, reverse flow inflators which initially provide or supply a relatively cool inflation gas, followed by heated or elevated temperature inflation gas to an associated airbag cushion, can typically more easily provide or result in the more gradual deployment of the associated airbag cushion, as may be desired in particular deployment applications.
In inflatable passive restraint system design, the space requirement (commonly referred to as the “envelope”) for the airbag inflator is commonly very important. The need for airbag inflators with smaller envelopes can be particularly crucial for applications involving inflation of restraint elements such as inflatable curtains. In particular, inflatable curtain cushions tend to have rather large inflation volumes while market needs, dictated at least in part by available packaging volumes, call for inflators characterized by relatively small volumes. For example, some common inflatable curtain airbag cushions have inflation volumes of up to 40 liters while an inflator envelope of no larger than about 30 mm in diameter and 400 mm in length is permitted.
One approach to satisfying the need and demand for smaller sized inflator devices capable of providing relatively large volumes of inflation gas is via the use of liquified gases such as disclosed in commonly assigned Rink, U.S. Pat. No. 5,669,629, issued Sep. 23, 1997; Rink et al., U.S. Pat. No. 5,884,938, issued Mar. 23, 1999; and Rink et al., U.S. Pat. No. 5,941,562, issued Aug. 24, 1999, for example and the disclosures of which patents are hereby incorporated by reference herein in their entirety and made a part hereof. In such an approach, the increased density of liquified gases (as compared to similar gaseous phase systems) permits the storage of a much greater mass of material in an identical volume.
The heating and/or dissociation of such stored liquids can, howev
Blakemore David L.
Green David J.
Rink Karl K.
Young Anthony M.
Autoliv ASP Inc.
Brown Sally J.
Erickson James D.
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