Land vehicles – Wheeled – Attachment
Reexamination Certificate
1998-01-09
2001-01-09
Culbreth, Eric (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S741000, C280S742000
Reexamination Certificate
active
06170867
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to inflatable restraint systems and, more particularly, to an apparatus and method for inflating an inflatable device such as an inflatable vehicle occupant restraint for use in such systems.
It is well known to protect a vehicle occupant using a cushion or bag, e.g., an “airbag cushion,” 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 to be 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 the inflating of one or more inflatable restraint system airbag cushions. Prior art inflator devices include compressed stored gas inflators, pyrotechnic inflators and hybrid inflators. Unfortunately, each of these types of inflator devices has been subject to certain disadvantages such as greater than desired weight and space requirements, production of undesired or non-preferred combustion products in greater than desired amounts, and production or emission of gases at a greater than desired temperature, for example.
In view of these and other related or similar problems and shortcomings of prior inflator devices, a new type of inflator, called a “fluid fueled inflator,” has been developed. Such inflators are the subject of commonly assigned Smith et al., U.S. Pat. No. 5,470,104, issued Nov. 28, 1995; Rink, U.S. Pat. No. 5,494,312, issued Feb. 27, 1996; and Rink et al., U.S. Pat. No. 5,531,473, issued Jul. 2, 1996, the disclosures of which are filly incorporated herein by reference.
Such inflator devices typically utilize a fuel material in the form of a fluid, e.g., in the form of a gas, liquid, finely divided solid, or one or more combinations thereof, in the formation of an inflation gas for an airbag. In one such inflator device, the fluid fuel material is burned to produce gas which contacts a quantity of stored pressurized gas to produce inflation gas for use in inflating a respective inflatable device.
While such an inflator can successfully overcome, at least in part, some of the problems commonly associated with the above-identified prior types of inflator devices, there is a continuing need and demand for further improvements in safety, simplicity, effectiveness, economy and reliability in the apparatus and techniques used for inflating an inflatable device such as an airbag cushion.
To that end, the above-identified Rink, U.S. Pat. No. 5,669,629 discloses a new type of inflator wherein a gas source material undergoes decomposition to form decomposition products including at least one gaseous decomposition product used to inflate an inflatable device.
Such an inflator can be helpful in one or more of the following respects: reduction or minimization of concerns regarding the handling of content materials; production of relatively low temperature, non-harmful inflation gases; reduction or minimization of size and space requirements and avoidance or minimization of the risks or dangers of the gas producing or forming materials undergoing degradation (thermal or otherwise) over time as the inflator awaits activation.
There is, however, a continuing need and demand for further improvements in safety, simplicity, effectiveness, economy and reliability in the apparatus and techniques used for inflating an inflatable device such as an airbag cushion. More specifically, there is a need and a demand for an inflator device which can provide at least some of the benefits provided by the inflator of the above-identified Rink, U.S. Pat. No. 5,669,629, wherein a gas source material undergoes decomposition to form decomposition products including at least one gaseous decomposition product used to inflate an inflatable device even when sized to provide desired inflation of the typically larger sized, e.g., larger volume, airbag cushions associated with passenger side airbag inflatable restraint systems.
SUMMARY OF THE INVENTION
A general object of the invention is to provide an improved apparatus and method for inflating an inflatable device such as an inflatable vehicle occupant restraint for use in such inflatable restraint systems.
A more specific objective of the invention is to overcome one or more of the problems described above.
The general object of the invention can be attained, at least in part, through a specified apparatus for inflating an inflatable device. The apparatus includes a first chamber and an ignition assembly. The first chamber contains at least one gas source material which undergoes decomposition to form decomposition products which include at least one gaseous decomposition product used to inflate the device. The ignition assembly includes a linear ignition source to initiate the decomposition of the at least one gas source material in the first chamber and an initiator to ignite the linear ignition source.
The prior art fails to provide an as effective as desired apparatus and method for inflating an inflatable device wherein a gas source material undergoes decomposition to form decomposition products including at least one gaseous decomposition product used to inflate an inflatable device even when sized to provide desired inflation of the typically larger sized, e.g., larger volume, airbag cushions associated with passenger side airbag inflatable restraint systems.
The invention further comprehends an apparatus for inflating an inflatable device in accordance with an alternative embodiment of the invention. Such apparatus includes a first chamber which contains a gas source material of nitrous oxide which undergoes decomposition to form decomposition products including at least one gaseous decomposition product used to inflate the device. The apparatus also includes an ignition assembly. The ignition assembly includes an ignition transfer line to initiate decomposition of at least a portion of the nitrous oxide in the first chamber and an initiator to ignite the ignition transfer line.
The invention still further comprehends methods for inflating an inflatable safety device in a vehicle.
One such method involves igniting a linear ignition source housed within a first chamber of an inflation apparatus and extending for a length therein. Additionally housed within the first chamber, in contact with the linear ignition source, is at least one gas source material. At least a portion of the at least one gas source material in contact with an ignited portion of the linear ignition source decomposes to form decomposition products including at least one gaseous decomposition product. The inflation apparatus subsequently releases inflation gas including at least a portion of the at least one gaseous decomposition product to inflate the inflatable safety device.
As used herein, references to “combustion,” “combustion reactions” and the like are to be understood to generally refer to the exothermic reaction of a fuel with an oxidant.
References to “decomposition,” “decomposition reactions” and the like are to be understood to refer to the splitting, dissociation or fragmentation of a single molecular species into two or more entities.
“Thermal decomposition” is a decomposition controlled primarily by temperature. It will be appreciated that while pressure may, in a complex manner, also influence a thermal decomposition such as perhaps by changing the threshold temperature required for the decomposition reaction to initiate or, for example, at a higher operating pressure change the energy which may be required for the decomposition reaction to be completed, such decomposition reactions remain primarily temperature controlled.
“Exothermic thermal decomposition” is a thermal decomposition which liberates heat.
As identified above, the term “equivalence ratio” (&phgr;) is an expression commonly used in reference to combustion and comb
Green David J.
Rink Karl K.
Autoliv ASP Inc.
Brown Sally J.
Culbreth Eric
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