Land vehicles – Wheeled – Attachment
Reexamination Certificate
2001-08-01
2003-02-18
Olszewski, Robert P. (Department: 3627)
Land vehicles
Wheeled
Attachment
C280S736000, C280S735000
Reexamination Certificate
active
06520538
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to an air bag gas generator and air bag system for protecting a passenger from impacts, and in particular, a gas generator for an air bag using an igniting means which includes an initiator that is activated by an electrical signal.
DESCRIPTION OF THE RELATED ART
An air bag system is attached to a vehicle, such as an automobile, etc., for the purpose of protecting a passenger from an impact due to a collision. In this air bag system, when a sensor detects an impact, a gas generator is activated, and a cushion (air bag) is formed between the passenger and the vehicle. The gas generator is activated in such a way that the sensing of the impact by the impact sensor activates igniting means, causing gas generating means to burn and generate a combustion gas. Conventionally, for such a gas generator, there are a mechanical ignition type gas generator, which is activated by sensing an impact exclusively by means of a mechanical method, and an electrical ignition type gas generator, which is activated by an electrical signal transmitted from an impact sensor, such as a semiconductor-type acceleration sensor, etc., that senses an impact.
Among these gas generators, in the electrical ignition type gas generator, in particular, the signal from the electrical sensor upon detection of an impact, is transmitted via a lead wire to an initiator which is contained in the housing. The initiator is activated by the electrical signal to ignite and burn an enhancer. The flame from the burning enhancer ignites and burns gas generating means to generate combustion gas. Also, the initiator may, in some cases, directly ignite and burn the gas generating agents instead of the enhancer. The combustion gas generated in the housing flows into the air bag from gas discharge ports provided in the housing. Therefore, in the electrical ignition type gas generator, it is necessary for the initiator, which is contained in the housing and actually activates the gas generator, to be connected to the electrical sensor, which senses the impact and outputs a signal, provided outside the housing.
However, the lead wire extending from the initiator has a directional property. Therefore, in the conventional gas generator for an air bag, the lead wire would be slack or too short depending on the direction which the initiator has been installed, causing the lead wire to be too short for connecting to the electrical sensor.
SUMMARY OF THE INVENTION
The present invention solves these problems found in the above-mentioned conventional air bag gas generator and provides an air bag gas generator which ensures that the length of the lead wire is sufficient, even if the length of the connector in the air bag gas generator is predetermined, when installing this gas generator in the module.
The air bag gas generator according to the present invention is characterized in that it uses igniting means having an initiator, which is exclusively activated by an electrical signal and by installing the ignitor in the housing after the initiator has been positioned.
That is, the air bag gas generator of the present invention comprises, in a housing having gas discharge ports and an igniting means storage hole: igniting means activated by an impact; gas generating means ignited by the igniting means and burns and generates a combustion gas; and a coolant/filter, which cools the combustion gas and/or collects the combustion residue; and by having the igniting means composed to include an initiator which is activated by an electrical signal, with the initiator being positioned and then installed in the housing.
The positioning of the initiator can be done, for instance, by forming a positioning portion in the initiator collar, to which the lower portion of the initiator is fitted, forming, in an insertion jig for inserting the initiator, an engaging portion which engages the positioning portion in the initiator collar, and engaging the positioning portion of the initiator collar with the engaging portion in the insertion jig. Such a positioning portion can be obtained by forming a step helix by cutting a portion of the bottom surface of the initiator collar into a step helix form in the radial direction while retaining the edge portion thereof, or by forming a groove by cutting a portion of the bottom surface of the initiator collar in the radial direction. Especially, when the positioning portion is formed by cutting a portion of the bottom surface of the initiator collar into the step helix form in the radial direction, while retaining the circumference of the initiator collar, the air bag gas generator which utilizes the initiator can, even when in operation, more securely and advantageously prevent the leakage of the combustion gas from any gap between the inner surface of the portion containing the initiator and the outer circumferential surface of the initiator collar.
The engagement between the positioning portion of the initiator collar and the engaging portion of the insertion jig is achieved, for instance, by: forming the engaging portion of the insertion jig as a fitting protrusion which complementarily fits in the positioning portion formed as described above; complementarily fitting the fitting protrusion to the above-mentioned positioning portion; and disposing the initiator in the housing while positioning it. When a gas generator attachment portion, which attaches the air bag gas generator to a module case, is formed in the housing and the initiator is positioned with respect to the gas generator attachment portion, it is possible to position the initiator using the insertion jig that has been positioned to the gas generator attachment portion and then install the initiator in the housing. By positioning the initiator and then installing it in the housing, the orientation of the electric conductive terminals of the initiator becomes constant. As a result, the lead wire can be drawn in a fixed direction, allowing a reliable connection of the initiator and the sensor with the lead wire. With respect to the positioning of the initiator, aside from using the insertion jig as described above, the initiator can also be positioned by forming, for instance, a groove or protrusion in the storage opening for storing the initiator and also forming, on the outer circumferential surface of the initiator or the initiator collar provided at the lower portion of the initiator collar, a protrusion or groove which complementarily fits the groove or protrusion formed in the above-mentioned storage opening for the initiator, and then fitting them together.
In the present invention, except for the initiator and initiator collar, any conventionally used elements required to operate the gas generator, such as a “housing” having gas discharge ports, “gas generating means” for generating gas by combustion, “filter means” for purifying and cooling the generated gas, can be used. Further, other structures and members for an air bag gas generator advantageous to the operation of the air bag gas generator, such as: an “inner cylindrical member,” which partitions the inside of the housing into two or more chambers; a “filter support member,” which is provided between the inner cylindrical member and the filter means, and which supports the filter means; “short-pass preventing means (plate member, etc.),” which encloses the top end and/or bottom end of the inner circumference of the filter means and which prevents the gas generated from passing through the gap between the filter means and housing inner surface; a “cushion member,” which is provided above and/or below the gas generating means to prohibits the gas generating means from moving; a “perforated basket,” which has multiple holes, is cylindrical in shape, and is provided on the inner side of the filter means to prevent the gas generating means from directly contacting the filter means and to also protect the filter means from the flames from the combustion of the gas generating means; and a “plenum,” which is provided between the outer surface of
Katsuda Nobuyuki
Tomiyama Shogo
Birch & Stewart Kolasch & Birch, LLP
Daicel Chemical Industries Ltd.
McClellan James S.
Olszewski Robert P.
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