Land vehicles – Wheeled – Attachment
Reexamination Certificate
1999-12-20
2001-08-21
Rice, Kenneth R. (Department: 2167)
Land vehicles
Wheeled
Attachment
C280S740000, C264S155000
Reexamination Certificate
active
06276717
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a cushion employed in an air bag gas generator, which protects a passenger from an impact. It also directed to an air bag gas generator, which employs such a cushion member.
DESCRIPTION OF THE RELATED ART
A gas generator for an air bag usually comprises, within a housing having gas discharge ports: igniting means which is activated on impact; gas generating agents, which are ignited upon activation of the igniting means and burn to produce a combustion gas; a filter, which purifies the combustion gas, and/or a coolant, which cools the combustion gas. Solid gas generating agents, which are formed into a suitable shape, are normally used as the gas generating agents. If the gas generating agents are provided in the housing as they are, the agents may break due to their movement within the housing or by the vibration of the gas generator.
Therefore, in a conventional gas generator, the gas generating agents, etc., contained in the housing are supported by a suitable support member to prohibit their movement or destruction.
In a conventional art, the art of combining a ceramic fiber plate and a spring such that the spring supports, by its elasticity, the plate having a ceramic fiber layer, and supporting the agents by the layer is disclosed as the support member (U.S. Pat. No. 4,590,041). In another conventional art, the art of providing an inactive spacing pad between the agents and an inner surface of the housing to prevent movement of the agent is disclosed (U.S. Pat. No. 4,902,036) as the support member.
However, when the gas generating agents are supported in the above-described manner, a sufficient elastic force cannot be obtained since the support members are made of fiber. Therefore, these support members are not for prohibiting the movement of the gas generating agents.
SUMMARY OF THE INVENTION
The present invention resolves the above-mentioned problems by providing an air bag gas generator having a cushion member having a sufficient elasticity to fix the gas generating agents and which can also be easily manufactured. It is also an object of the present invention to provide an air bag gas generator, which uses such a cushion member.
The cushion member for an air bag gas generator of the present invention is characterized in that: in a cushion member for prohibiting movement of a member contained in a housing, a surface characteristic of an upper or a lower surface, or both surfaces of the cushion member has a surface characteristic where when cushion members are stacked together, the surfaces of each cushion member do not stick together. These cushion members are often contained in the housing for the purpose of supporting the gas generating agents, but are not limited thereto. They can also be contained at a suitable location within the housing in order to prohibit movement of other members contained in the housing, such as a transfer charge, etc., contained in the igniting means.
As a preferable surface characteristic of the cushion member, a surface roughness Ra of the cushion member is to be 1 &mgr;m or less by the JIS B-0601 test method. The cushion member having such a surface characteristic can be formed by stacking multiple sheets, made of a synthetic macromolecular resin having a non-adhering surface characteristic even when they are stacked together (e.g., a surface characteristic of 1 &mgr;m or less in surface roughness Ra by the JIS B-0601 test method), and then stamping out the stacked sheets. A sheet having such a surface characteristic can be formed by sandwiching a synthetic macromolecular resin, such as a silicon foam, etc., between PET sheets, etc., having a surface characteristic of 1 &mgr;m or less in surface roughness Ra by the JIS B-0601 test method, and then by peeling off the PET sheets on the upper and lower surfaces thereof. The manufacturing method for the cushion member of the present invention is not limited thereto, and it is also possible to obtain a cushion member having the above characteristic by stamping out a synthetic macromolecular resin with no prescribed surface characteristic, and then providing an appropriate surface treatment, such as rough surface treatment, on its surfaces to obtain the foregoing surface characteristic.
The cushion member of the present invention is intended to prohibit movement, in particular, of a member contained in an air bag gas generator, such as gas generating agents, a transfer charge, etc. If the member whose movement is prohibited by the cushion member is the gas generating agents, it is desirable for the cushion member to have almost the same shape as the plane shape of the combustion chamber, in which the above-mentioned gas generating agents are contained within the housing, for example, a ring shape having an outer diameter of 38-47 mm, an inner diameter of 20-35 mm, and a thickness of 1.0-9.0 mm, or a disc shape having the same outer diameter and thickness as in the ring shaped cushion member, etc. Further, when the cushion member supports a transfer charge of the igniting means installed in the igniting means storage chamber, the cushion member can have almost the same shape as the plane shape of the igniting means storage chamber, for instance, an almost disc shape with an outer diameter of 10-16 mm and a thickness of 1.0-6.0 mm.
The cushion member is provided within the housing, having gas discharge ports, along with the igniting means, which is activated on impact, the gas generating agents, which are ignited upon activation of the igniting means, and burn to generate the combustion gas, and a coolant/filter, which cools the combustion gas and/or collects combustion residues, etc, and the cushion member supports the gas generating agents, thus forming a complete air bag gas generator.
The above-mentioned housing can be formed by casting, forging, or press work, etc., and it is preferably formed by welding a diffuser shell having gas discharge ports and a closure shell having an igniting means storage opening. The two shells can be joined by various welding methods, such as electron-beam welding, laser welding, TIG welding, projection welding, etc. When the diffuser shell and the closure shell are formed by press-molding various types of steel sheet, such as stainless steel sheets, etc., the manufacture of the two shells is made easy and a reduction in manufacturing cost is achieved. By forming the two shells into simple, cylindrical shapes, the press-molding becomes easy. As for the material for the diffuser shell and the closure shell, stainless steel sheets are desirable, but nickel-plated steel sheets may also be used. Moreover, one or more inner cylindrical members can be provided within the housing, as desired, to partition interior space into two or more chambers.
The above-mentioned cushion member is provided on the side of the closure shell and/or the side of the diffuser shell within the housing and can support any members installed in the housing. Therefore, a pair of cushion members can be installed within the housing in an opposing relationship, such that a member installed in the housing, such as a gas generating agents, sandwiched between the cushion members and supported by the cushion members.
The above-mentioned igniting means, which is activated upon impact, can either be mechanical-ignition type igniting means, which is activated by sensing an impact exclusively by means of a mechanical method, or electrical-ignition type igniting means, which is activated by an electrical signal transmitted from an impact sensor that senses an impact.
The mechanical-ignition type igniting means includes: a mechanical-type sensor, which senses an impact via an exclusively mechanical method such as the firing of a firing pin via the movement of a weight, etc.; a detonator, which is ignited when struck by the firing pin fired from the above-mentioned mechanical-type sensor and then burns; and a transfer charge, which is ignited by the flame from the detonator and then burns. On the other hand, the electrical-ignition type igniting
Katsuda Nobuyuki
Sanda Kenji
Daicel Chemical Industries Ltd.
Jasmin Lynda
Rice Kenneth R.
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