Land vehicles – Wheeled – Attachment
Reexamination Certificate
1998-10-28
2001-05-15
Culbreth, Eric (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S735000, C280S742000
Reexamination Certificate
active
06231075
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automotive air bag system for protecting a passenger from injuring by an impact of a collision and, more specifically to the automotive air bag system with an inflator for inflating an air bag at a slow speed.
2. Description of the Related Art
As is generally known, an automotive air bag system has an air bag inflator which generates a gas quickly when a high acceleration is imparted to a vehicle due to, for example, a collision of the vehicle against an obstacle. The air bag is inflated under various conditions requiring different inflating speeds. Various inflating speed controllers have been proposed in, for example, JP-A Nos. 5-24498 and 7-251694, and JP-U No. 6-1029.
The inflating speed controller proposed in JP-A No. 5-24498 controls the inflating speed of the air bag by operating a valve plate by a gas generated by an inflator to control the amount of intake air by closing an air inlet opening formed in a holding box when the ambient temperature is high so that the air bag can be inflated at a substantially fixed inflating speed regardless of the variation of the ambient temperature.
The inflating speed controller proposed in JP-U No. 6-1029 controls the inflating speed of the air bag by breaking a resin plate formed on an air bag case by an internal pressure of the air bag to reduce the internal pressure of the air bag to avoid imparting an excessively high impact on a vehicle passenger the suddenly inflating air bag when the air bag is unable to inflate smoothly at the initial stage of inflation and starts inflating suddenly due to the sharp increase of the internal pressure of the air bag.
The inflating speed controller proposed in JP-A No. 7-251694 supplies a gas generated by an inflator through a narrow passage to an air bag to inflate the air bag at a relatively low inflating speed at the initial stage of combustion in the inflator, and removes a baffle plate disposed in the gas passage by the pressure of the gas increasing with the progress of combustion in the inflator to expand the gas passage so that the inflating speed of the air bag is increased to avoid imparting a sudden impact to an infant or a vehicle passenger by the sudden inflation of the air bag at the initial stage of inflation.
No prior art inflating speed controllers can control the inflation of the air bag properly and the air bag is inflated at an excessively high inflating speed when the vehicle collides lightly against an obstacle while the vehicle is traveling at a relatively low traveling speed and a relatively light shock is exerted on the vehicle. Generally, the air bag is provided with a gas discharging hole to absorb energy moderately, and the air bag is held fully inflated only a very short time. The data on the air bag are determined for appropriately securing the passenger from a strong impact that may be imparted to the passenger when the vehicle collides with an obstacle while traveling at a very high speed. Therefore, the passenger will plunge into the air bag after the air bag has been fully inflated and has started deflating if the vehicle collides against an obstacle with a relatively low impact while the same is traveling at a low traveling speed, and the function of the air bag may not fully be utilized.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an automotive air bag inflator for controlling an inflating speed of an air bag according to an intensity of an impact in dependency on collision modes of the vehicle against an obstacle, so that the air bag is inflated at a very high inflating speed to protect a passenger when the intensity of the impact is high, and the air bag is inflated at a reduced inflating speed when the intensity of the impact is low.
According to a first aspect of the present invention, an automotive air bag system mounted on the vehicle has an inflator, an impact sensor for measuring a magnitude of an impact exerted on the vehicle, first gas generating means for generating a gas for inflating an air bag, a housing with gas jetting openings in a wall, gas flow restricting means for restricting a gas flow through the gas jetting openings, second gas generating means for operating the gas flow restricting means, and a controller for controlling the first and the second gas generating means on the basis of a collision signal provided by the impact sensor. In this automotive air bag system, the controller initiates the first gas generating means to inflate the air bag upon receiving the collision signal provided by the impact sensor, and it initiates the second gas generating means to operate the gas flow restricting means so that a flow rate of the gas into the air bag is limited when the magnitude of the impact measured by the impact sensor is below a predetermined threshold value.
In the automotive air bag system, the controller may initiate the second gas generating means when an integral of the collision signal provided by the collision sensor for a predetermined time is less than a predetermined value.
In the automotive air bag system, the gas flow restricting means may be a movable shutter which reduces the area of each of the gas jettison holes to reduce the rate of flow of the gas into the air bag.
Preferably, the movable shutter has a peripheral part slidably fitted in the housing, and a sealing part for defining a sealed space together with the second gas generating means, and the movable shutter may be forced to slide and held at a position to reduce the area of each of the gas jettison holes when a gas is generated in the sealed space by initiating the second gas generating means.
The automotive air bag system may further comprise a seat belt sensor for monitoring whether or not a seat belt is fastened to hold a passenger on a seat, and the controller may inhibit initiate the second gas generating means when the seat belt sensor provides a signal indicating that the seat belt is not fastened.
When the vehicle receives a strong impact upon collision with another object, the controller provides a gas jetting signal to the first gas generating means to generate a gas suddenly. The generated gas is jetted through the gas jettison holes into the air bag to inflate the air bag. At this stage, the second gas jetting signal is not provided and the gas jettison hole is not closed by the movable shutter, Therefore, the gas jettison hole has a large area and the air bag is inflated in a moment to protect the passenger.
REFERENCES:
patent: 5433475 (1995-07-01), Kokeguchi
patent: 5618057 (1997-04-01), Johnson et al.
patent: 5785347 (1998-07-01), Adolph et al.
patent: 5820162 (1998-10-01), Fink
patent: 6022045 (1998-10-01), Faigle
patent: 6036225 (2000-03-01), Foo et al.
patent: 5-24498 (1993-02-01), None
patent: 6-1029 U (1994-01-01), None
patent: 7-251694 (1995-10-01), None
English Language Abstract for Japanese Publication No. 05024498.
English Language Abstract for Japanese Publication No. 06001029.
Culbreth Eric
Fuji Jukogyo Kabushiki Kaisha
Smith Gambrell & Russell
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