Land vehicles – Wheeled – Attachment
Reexamination Certificate
1999-09-01
2001-07-03
Mai, Lanna (Department: 3619)
Land vehicles
Wheeled
Attachment
C280S737000, C280S741000, C137S068130, C137S068300, C222S005000
Reexamination Certificate
active
06254128
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a hybrid gas generator for an air bag.
A hybrid gas generator is known from EP 0 616 578 B1 which contains a gas-generating solid charge and a storage gas. In the event of initiation, the solid material charge is ignited by an ignition element. As a result of this, a sliding piston is advanced in the direction of the storage chamber. The sliding piston contains a first bursting disc, and the closing element of the storage chamber represents a second bursting disc. After the ignition of the solid charge, the second bursting disc which closes the storage chamber is to be destroyed first, so that cold gas arrives in the air bag. The second bursting disc is to be destroyed thereafter by means of the pressure which continues to build up in the combustion chamber, so that hot gas penetrates into the storage chamber and heats the storage gas still present there. The proper functioning of this gas generator depends on the bursting behaviour of the two bursting discs. In particular the bursting disc provided at the sliding piston must be destroyed at a precisely defined pressure. The bursting disc provided at the sliding piston must open in dependence upon the pressure of the combustion gases, whereas the bursting disc which closes the storage chamber is destroyed in dependence upon the path of the sliding piston. These different dependencies have the result that the pressure build-up behaviour of the gas generator can be subjected to considerable manufacturing tolerances. The characteristic of the pressure increase in the combustion chamber and the burning characteristic must be carefully matched to the strength of the predetermined breaking points of the bursting discs, with the result that the manufacture of the gas generator requires very high levels of precision.
SUMMARY OF THE INVENTION
The object of the invention is to create a hybrid gas generator which, with simple assembly, has a reliable and reproducible operating performance and is therefore suitable for easy and economical mass production.
The object is achieved in accordance with the invention by providing a hybrid gas generator for an air bag, having a cartridge arranged in a guide channel, the cartridge containing an ignitable, gas-generated solid charge, a storage chamber closed by a closing element and containing a storage gas, and a tubular sliding element displaceable by the reaction gases of the solid charge toward the closing element and pushing the closing element open. The cartridge has a front wall which can be torn away by the reaction gases of the solid charge, with the front wall advancing, after the tearing-away, into a flow zone of larger cross section than the guide channel. The sliding element has at least one lateral opening through which the reaction gases flow out of the flow zone into the sliding element.
With the gas generator in accordance with the invention the release of the combustion gases and also the release of the storage gas take place accordance to the path of the sliding element. Because both gases are therefore controlled according to the path of the same part (sliding element), there is an exact and reproducible operating performance which is largely independent of the pressure build-up characteristic of the respective solid charge. In particular, by suitable selection of the linear dimensions of the sliding element, the flow zone and the length of the sliding-element path, the course of the pressure build-up with time can be established. Through the construction and the geometric constraint it can be guaranteed that cold storage gas flows out of the hybrid gas generator first, and that only thereafter does the mixture of the cold storage gas and the hot reaction gas flow out. Advantages of this sequence are a reduced thermal load on the air bag by gases and a lower gas pressure in the storage chamber when the reaction gas flows in.
According to a preferred development of the invention the cartridge has a retaining band projecting axially over the front wall, the retaining band being bent around an edge of the sliding element. In this way, the front wall is used, on the one hand, as a boundary for the cartridge and, on the other hand, as a carrier of the tubular sliding element. In this way, there exists the possibility of an easy and economical mass production and of a pyrotechnic cartridge which can be installed separately. Alternatively, the tubular sliding element can also be a one-part component of the cartridge.
According to a preferred development of the invention a conical section on the sliding element makes possible a smooth braking of the sliding element in the end position, and, as a result of the self-locking effect, a defined end position of the sliding element.
REFERENCES:
patent: 5230531 (1993-07-01), Hamilton et al.
patent: 5242194 (1993-09-01), Popek
patent: 5257819 (1993-11-01), Frantom et al.
patent: 5273312 (1993-12-01), Coultas et al.
patent: 5344186 (1994-09-01), Bergerson et al.
patent: 5345876 (1994-09-01), Rose et al.
patent: 5351989 (1994-10-01), Popek et al.
patent: 5582426 (1996-12-01), O'Loughlin et al.
patent: 5584505 (1996-12-01), O'Loughlin et al.
patent: 5649720 (1997-07-01), Rink et al.
patent: 5653463 (1997-08-01), Jeong
patent: 5659295 (1997-08-01), Renfroe et al.
patent: 5779266 (1998-07-01), Moore et al.
patent: 5931495 (1999-08-01), Rink et al.
patent: 6010153 (2000-01-01), Halas et al.
Albrecht Uwe
Bretfeld Anton
Kraft Josef
Zhang Jiang
Antonelli Terry Stout & Kraus LLP
Dynamit Nobel GmbH Explosivstoff-und Systemtechnik
Mai Lanna
To Toan
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