Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
2000-09-26
2002-12-03
Nguyen, Tan (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C701S045000, C280S730100, C180S273000
Reexamination Certificate
active
06490515
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a passenger detecting apparatus which determines the presence of a passenger or an object, such as a child seat, on a seat apparatus, accurately estimates the weight of a passenger, or determines or classifies the build or the seating posture of a passenger seated on a seat.
BACKGROUND ART
Passenger restraint systems, such as an air bag system, a seat-belt pretensioner and a force limiter are often equipped around, for example, the seat apparatus of an automobile to secure the safety of a passenger. If those passenger restraining systems are used inadequately or wrong, however, the passenger restraint systems may hurt a passenger. If an air bag is activated while a woman of small build is driving with her face close to the steering wheel, the abrupt inflation of the air bag may cause a face injury. If an air bag is activated with a child sitting in the front of a front passenger seat, the inflation of the air bag likewise may injure the child.
To prevent harmful effects from being done by the restraint systems that should guarantee safety of a passenger, it is desirable to adequately activate the passenger restraint systems around the seat apparatus in accordance with the build of a passenger seated on a seat.
In a case of an air bag system, for example, there is a demand of attaching a passenger detecting apparatus to a seat unit to determine the build of a passenger and performing such control as to inflate the air bag normally when the passenger is determined as an adult of a standard size, to slow the air-bag bag inflation time when the passenger is determined as an adult of small build and not to inflate the air bag and secure safety only with a seat belt when the passenger is determined as a child.
Accordingly, consideration is given to what is called a smart air bag system which controls an air bag in accordance with the build of a passenger. There are various systems of using the position or the like of a passenger on a seat besides build information such as the weight and height, as threshold values for the build of a passenger. Of those systems, the most promising one is the system that controls an air bag according to the build information of a passenger. Specifically, this system determines the weight of a passenger to make classification and controls the air-bag inflation time, air-bag inflation strength or the like.
One example of a passenger detecting system which makes such decisions as to if a passenger is in a danger zone and whether the passenger is a child or an adult is introduced in U.S. Pat. Nos. 5,573,269 and 5,670,853.
The passenger detecting systems described in those publications have weight sensors located around a seat, i.e., under the seat, under the seat fabric and under the floor mat under feet, a back-rest angle sensor located in the back rest and a height sensor located above a passenger and detect the weight and position of the passenger by a combination of those sensors.
Those systems combine at least four sensors, which lead to a higher cost.
In the case where a load sensor is provided under a seat, to accurately detect the weight of a passenger, it is necessary to consider the load applied under the feet of the passenger in addition to the load detected by this load sensor. If a weight sensor is located under the floor mat as described in the aforementioned publications to acquire the load applied under the feet, the positions of the feet of a passenger differ depending on the build and posture of the passenger. This makes it difficult to accurately detect the load applied under the feet.
That is, to measure the value of the load on a seat and control the air-bag inflation time and air-bag inflation strength in accordance with the weight of a passenger, the accurate weight information of the passenger should be acquired. Even with a combination of a plurality of sensors, instruments or the like, it is difficult to make accurate measurements due to the posture of a passenger, a change in ambient temperature, a change in humidity, vibration of a vehicle and so forth. In this respect, in consideration of a variation of each measured value, it seems adequate to classify the weight of a passenger into classes having certain ranges.
It is also necessary to consider a case where an infant or a child is seated in a child seat (an auxiliary seat for a child including an infant seat and a booster seat). Specifically, the height to the head of an infant or a child, the distance to the dash board, the restraint force to the seat and so forth greatly differ from those in the case where a female adult of small build is seated. It is therefore demanded not to activate the supplemental systems around a seat, such as an air bag, unnecessarily. Since the value of the load applied to a seat in the case where a child is seated using a child seat is close to the load value in the case where a female adult of small build is seated, however, accurate passenger information may not be obtained so that the supplemental systems around a seat, such as an air bag, may be activated unnecessarily. Therefore, it is also necessary to adequately classify the weight of a passenger and to securely detect, particularly, the case where an infant or a child is seated on the car seat via a child seat.
There has been an antenna/tag system which has a tag provided on a child seat side and determines whether or not a child seat is in use by emitting radio waves toward the tag from a seat unit to detect the presence of the tag. While it is possible to determine whether or not a child seat is in use using this system, such a tag should not necessarily be provided on a child seat and when a child seat without such a tag is attached to the seat unit, the passenger detecting apparatus may erroneously determine that an adult is seated on the seat unit, resulting in an unnecessary activation of restraint systems, such as an air bag.
Japanese Unexamined Patent Publication (KOKAI) No. Hei 9-150662 discloses the structure that has a distortion gauge provided between a seat cushion and a plurality of brackets for securing the seat cushion to the floor of a vehicle. This structure merely makes reliable detection of the presence or absence of a seated person without being influenced by the seating position of the seated person on a seat, but cannot adequately classify the weight of a passenger on a seat and surely detect, particularly, the case where an infant or a child is seated on the seat via a child seat.
When the load that is applied to the seating surface using a passenger detecting apparatus, just changing the angle of the back rest, for example, significantly changes the load applied to the seating surface even if the same person is seated. This makes it difficult to estimate the size of the passenger's weight. Specifically, for example, the load that is applied to the seating surface in the case where a woman of small build is seated with the back rest set fully upright is close to the load in the case where a man of a standard size is seated with the back rest tilted slightly, so that the build cannot be determined accurately.
If such a type of passenger detecting apparatus is used in, for example, controlling an air bag, it is not possible to perform inflation of an air bag according to the build of a passenger seated on a seat or necessary inflation of a front-seat-passenger's air bag.
The aforementioned passenger detecting apparatus needs a sensor for detecting weight information to determine the build of a passenger. As this sensor, a load sensor for detecting the weight of a passenger has been proposed. Load sensors
410
a
to
410
d
are provided between a seat cushion pan
411
and springs
412
or a seat mounting section
413
to detect the weight of a passenger, as shown in FIG.
51
.
As the aforementioned load sensor, an electric capacitance type or a distortion gauge or the like is used. The electric capacitance type load sensor detects the weight from a change in the electric capacitance caused by a load-induced
Enomoto Takayuki
Hashimoto Kyosuke
Kuboki Naobumi
Negami Shoichi
Okamura Hiroyo
Knobbe Martens Olson & Bear LLP
Nguyen Tan
The Furukawa Electric Co. Ltd.
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