Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1999-02-03
2001-01-16
Zanelli, Michael J. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C701S029000, C701S035000
Reexamination Certificate
active
06175794
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control unit for an air bag and, in particular, to the control unit for the air bag which increases reliability of an operation of the air bag.
2. Description of the Related Art
In conventional air bag systems, an inflater and a control unit are housed in separated cases, and are connected with each other through a connector or the like. Such a conventional control unit after an inflation of the air bag is not different in appearance from the same before the inflation if it is separated from the inflater. This may lead to reuse of the control unit that has ever operated the inflater.
In the control unit, large electric current may flow when the inflater is ignited. The switch devices or the like therein may be damaged with the large electric currents. This means that the used control unit (i. e. the control unit which has ever made inflater operate) has only little reliability.
A memory unit for the air bag system is disclosed in Japanese Patent Laid-Open No. 18336 in 1997. The memory unit comprises a non-volatile memory device, and a microcomputer which can write acceleration data at certain intervals for the latest certain period into the non-volatile memory device when the air bag is inflated and which can then put the memory device under a ban on writing. According to the art, it is possible to know from the acceleration data written in the memory unit whether the inflation of the air bag was performed normally or abnormally. Additionally, it is possible to also know the delay time between the detection of the certain acceleration and the inflation of the air bag, if any.
However, the control unit for the air bag with the above memory unit after the inflation of the air bag is not different in appearance from the same before the inflation if it is separated from the inflater. This may lead to reuse of the used control unit that has ever operated the inflater.
As measures to prevent reuse of the control units after the inflation, there are operation manuals distributed by manufacturers, which tell operators not to reuse the control units.
However, only operators removing the control unit from the car can know whether it has made inflater operate or not. Therefore, it is possible for the control unit after the inflation to be on the market.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a control unit for an air bag which ensures prevention of the reuse thereof and to increase the reliability of the air bag.
In order to achieve the object, the control unit for the air bag according to the present invention, which is arranged between an inflater for the air bag and a power source generating a current for operating the inflater, comprises: storage means for storing an information of whether the inflater has been operated or not; a controller connected with the storage means for supplying a current for operating the inflater to the inflater on the basis of an operating information when the storage means do not store the information that the inflater has ever been operated; and warning means connected with the storage means for giving a warning when the storage means store the information that the inflater has ever been operated.
The controller may preferably be connected with a sensor for detecting an acceleration, which can give an operating information to the controller.
The controller may also be connected with an outside control unit having input means to give an operating information to the controller.
The storage means may comprise non-volatile storage means, preferably an EE-PROM which an information can be electrically written into and erased from.
The warning means may preferably be put on an instrument panel of a car.
According to the present invention, the storage means of the control unit for the air bag stores the inflation information, which indicates that the inflater has been operated, when the control unit supplies the current to the inflater and operates it. The control unit drives the warning means if it detects the inflation information in the storage means when setting the inflation. Any reuse of the control unit after the inflation can thus be prevented. This improves the reliability of the air bag system.
REFERENCES:
patent: 3877720 (1975-04-01), Upmeier et al.
patent: 4059822 (1977-11-01), Toshioka et al.
patent: 4848792 (1989-07-01), Breed
patent: 5721527 (1998-02-01), Simmons et al.
patent: 5847472 (1998-12-01), Byon
patent: 6043566 (2000-03-01), Bryant et al.
patent: 44 05 255 A1 (1995-08-01), None
Derwent Abstract; DE 29705400 U1; May 1997.
Abstract EPO; DE 4107538 A1; Sep. 1992.
Fuji Jukogyo Kabushiki Kaisha
Smith , Gambrell & Russell, LLP
Zanelli Michael J.
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