Land vehicles – Wheeled – Attachment
Reexamination Certificate
1998-11-16
2001-02-20
Dickson, Paul N. (Department: 3618)
Land vehicles
Wheeled
Attachment
C280S806000, C180S282000, C701S045000
Reexamination Certificate
active
06189923
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. HEI 10-31227, filed on Feb. 13, 1998, including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a manual cut-off system for passive safety devices and, more particularly, relates to such a system suited to accurately maintain operability of each of a plurality of air bags even after those air bags have been required to operate. The present invention also relates to a manual cut-off method for passive safety devices.
2. Description of Related Art
For example, U.S. Pat. No. 5,544,914 discloses a system wherein a vehicle passenger can manually change operability of an air bag.
The system according to this related art is equipped with a fuse connected in parallel with a squib corresponding to the air bag and a switch for selectively connecting a source of ignition signals to the squib or the fuse. When the air bag is required to operate, the source of ignition signals generates an ignition signal that is sufficient to ignite the squib and cut the fuse. The switch connects the source of ignition signals to the squib before the vehicle passenger requires that the air bag be capable of operation. On the other hand, if the vehicle passenger requires that the air bag be prevented from operating, the switch connects the source of ignition signals to the fuse.
If the air bag is required to be deployed under the circumstance where the vehicle passenger demands operation of the air bag, the ignition signal generated by the aforementioned source is supplied to the squib, thus deploying the air bag. On the other hand, if the air bag is required to be deployed under the circumstance where the vehicle passenger demands prevention of operation of the air bag, the ignition signal generated by the source is supplied to the fuse, thus cutting the fuse without deploying the air bag.
Hence, it is possible to determine whether or not the vehicle passenger had demanded prevention of operation of the air bag before a requirement for deployment thereof, by checking whether or not the fuse has been cut after the requirement for deployment of the air bag.
However, a surge current or a noise current may flow through the fuse. Thus, there is a possibility of the fuse being cut before arrival of the ignition signal. On the contrary, even if the ignition signal has been supplied to the fuse, the fuse may not be cut owing to, for example, characteristic errors or the like. Therefore, according to a system wherein the state manually set by the vehicle passenger is determined based on the state of the fuse, there is a possibility of an inaccurate judgement being made.
In addition, the system according to the related art is incapable of determining whether or not the switch for connecting the source of ignition signals to one of the squib and the fuse is in normal operation. Hence, even if there is a failure in the switch, the vehicle passenger is not informed of such a failure immediately.
Furthermore, in the case where a plurality of air bags are mounted to the vehicle, the system according to the related art requires that a plurality of switches and fuses be provided in correspondence with the respective air bags (as well as the respective squibs). For this reason, if the system according to the related art is employed in the case where a plurality of air bags are provided, the overall dimension of the system may increase substantially.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the aforementioned background. It is a first object of the present invention to provide a manual cut-off system that is applied to passive safety devices and reliably maintains manipulation states concerning operability of the passive safety devices, which include air bags. It is a second object of the present invention to provide a manual cut-off system that is applied to passive safety devices and is capable of immediately detecting a failure in a switch for changing operability of each of the passive safety devices.
Furthermore, it is a third object of the present invention to provide a manual cut-off system that is applied to passive safety devices and has a compact body (shape) even in the case where a plurality of passive safety devices, such as air bags, pretensioners and the like are mounted to the vehicle.
In order to achieve the first object, the manual cut-off system of the present invention is characterized by including passive safety devices, a switch that changes operability of each of the passive safety devices, a memory that stores a state of the switch, and a controller that prevents operation of control devices corresponding to those of the passive safety devices which are prevented from operating due to manipulation of the switch.
According to the aforementioned construction, if the vehicle passenger sets the switch to a position for preventing operation of some of the passive safety devices, control devices corresponding to those passive safety devices are prevented from operating. For example, in the case where those passive safety devices are air bags, an ignition signal is prevented from being supplied to squibs that are designed to deploy those air bags. Hence, if the switch is manipulated as described above, it is possible to prevent operation of the passive safety devices, regardless of whether they are required to operate. The state of the switch is stored in the memory. Accordingly, the state of the switch prior to a requirement for operation of the passive safety devices is reliably maintained even after the requirement has been established.
It is also effective to provide a memory lock for locking contents stored in the memory after the passive safety devices have been required to operate. According to this construction, the state of the switch stored in the memory is locked after a requirement for operation of the passive safety devices has been established. In this case, the contents stored in the memory cannot be changed after the requirement for operation of the passive safety devices has been established, so that the state of the switch is accurately maintained in the memory.
In addition to the aforementioned aspect, the second object is achieved by providing the manual cut-off system with a constant-current supplier that supplies a predetermined constant current to the switch, a plurality of system state indicators selectively connected to the switch, a plurality of resistors selectively connected to the switch, and a failure diagnosis controller that diagnoses a failure in a system including the switch, based on a voltage drop level determined in accordance with the constant current and a resistance value of one of the resistors.
According to the aforementioned construction, the constant current that has been supplied from the constant-current supplier flows through the switch, the system state indicator and the resistor connected to the switch. In this case, regardless of the state of the switch, the constant current always flows through the system state indicator. Thus, the system state indicator always emits light of a constant brightness. When the constant current that has been supplied from the constant-current supplier properly flows through the switch, the system state indicator and the resistor connected to the switch, the voltage drops by a level substantially corresponding to the resistance value of that resistor. In the present invention, it is determined accurately whether or not the switch is in normal operation, by checking whether or not the voltage drop level is suited for the constant current.
In addition to the aforementioned aspect, the third object is achieved by a construction wherein the passive safety devices include a plurality of air bags and at least one or more pretensioners and wherein the switch is a single multistage switch having a plurality of operation-preventing positions for preventing operation of a suitable combination of
Dickson Paul N.
Oliff & Berridg,e PLC
Toyota Jidosha & Kabushiki Kaisha
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