Seatbelt device

Details Seatbelt device Seatbelt device

2000-01-20

2001-02-06

Hofsass, Jeffery A. (Department: 2736)

Communications: electrical

Land vehicle alarms or indicators

Internal alarm or indicator responsive to a condition of the...

C340S457000, C280S804000, C280S806000

Reexamination Certificate

active

06184785

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a seatbelt device seeking the safety of a passenger by securing such passenger to a vehicle seat with a webbing (seatbelt), and particularly relates to a seatbelt device capable of controlling the operation of the collision-safety mechanism by providing to a buckle a function of detecting the passenger sitting in a seat or the fastening of a webbing.
2. Description of the Related Art
As an example of a conventional passenger detector for detecting the passenger in a vehicle, there is Japanese Patent Laid-Open Publication No. Hei 2-31964. This invention is provided with a supersonic sensor on the inner side of the door, and detects the existence of a passenger by utilizing the supersonic signals emitted from the supersonic sensor and the supersonic signals entering the supersonic sensor upon being reflected by the passenger.
Further, the invention of Japanese Patent Laid-Open Publication No. Hei 9-20194 proposes a structure wherein a sensor for detecting the passenger is arranged on the upper face of the dashboard and uses the inclined windshield as the sensor wave reflector so as to avoid the complexity of the cable wiring of supersonic sensors provided on the inner side of doors, and to seek and secure excellent reliability.
Moreover, detection of the fastening of a webbing is vital in a seatbelt device, and, for example, is conducted with a buckle switch provided within the buckle that engages with a tongue plate. A buckle sensor used for detecting the fastening of such webbing is demanded of high reliability in order to protect the passenger.
Nevertheless, with conventional passenger sensors arranged inside doors and on dashboards, the distance from the sensor to the passenger or the principle emission direction of the sensor wave and the passenger position is displaced upon the passenger sliding one's seat or reclining the backrest. Thus, in order to accurately detect the passenger, parameters such as the scope (sensitivity, directivity) of sensor detection distance must be corrected in conformity with the displacement of such sliding or reclining.
In addition, conventional buckle sensors did not go as far as to confirm whether the buckle switch was operating normally. One reason for this was due to the diagnosis of a buckle switch malfunction requiring a complex structure that would enable the compulsorily closing or opening of the buckle switch. Thus, such structure would not fit inside the buckle, or would make the buckle excessively large.
Moreover, it would be costly if the passenger sensor and buckle sensor were to be installed separately.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a seatbelt device comprising a passenger detector not easily affected by the sitting position or posture of the passenger.
Another object of the present invention is to provide a seatbelt device capable of diagnosing the malfunction of the seatbelt detector.
Still another object of the present invention is to provide a seatbelt device capable of detecting both the existence of a passenger and the fastening of a webbing.
The present invention for achieving the aforementioned objects is a seatbelt device for securing a passenger to a seat with a webbing, comprising: a tongue plate mounted on the webbing; a buckle which engages with the tongue plate and fastens the webbing to the passenger; and a passenger detector for detecting the existence of the passenger in the seat; wherein the passenger detector is provided inside the buckle.
By providing a passenger sensor to the buckle as mentioned above, the existence of the passenger may be detected when such passenger sits in his/her seat regardless of the sliding position or the reclining state of the seat. Thus, passenger detection may be conducted with more certainty.
Preferably, the seatbelt device comprises a control circuit for changing the threshold, which prevents the unnecessary activation of webbing locking or airbags upon collision, pursuant to detection signals showing the existence of a passenger. This control circuit further prevents unnecessary activation of webbing locking or airbags in consideration of the fastened or unfastened state of the webbing.
Preferably, the buckle is positioned at the side of the sitting passenger and supported in a position such that the passenger detector is capable of detecting the passenger. Further, the passenger detector may be provided to the face of the buckle facing the passenger and output sensor waves from a window of such face. The passenger detector includes an infrared sensor for detecting infrared rays emitted from the passenger. For example, this may be a pyroelectric infrared detector for detecting infrared rays via a filter for extruding infrared rays within wavelengths generated from a human body. With this detector, the fluctuation of temperatures (undulation of heat rays) caused by minute movements of the human body is also detected, and detection with minimal error is possible.
The passenger detector may be a sensor which discharges electromagnetic waves containing supersonic waves or light and detects the existence of a passenger pursuant to the reflective waves reflected by the passenger.
Preferably, a webbing fastening detector for detecting the engagement of the tongue plate and the buckle is further provided inside the buckle.
With this structure, the results of passenger existence and the fastened state of the webbing obtained by the passenger detector may be utilized for controlling the vehicle safety system seeking the safety of passengers, such as activation
on-activation of a webbing-locking mechanism of the pretensioner, activation
on-activation of the webbing tension unit, judgement of the activation
on-activation of an airbag, alteration of the threshold of such judgement, and so on.
Preferably, the webbing fastening detector includes: a non-contact detector provided inside the buckle and for generating, without contacting the tongue plate, the output corresponding to the existence of the tongue plate in the position where the tongue plate and the stopper mechanism of the buckle should engage; and a judgment element for judging the engagement
on-engagement of the tongue plate and the buckle from the output of the non-contact detector.
For example, the webbing fastening detector includes: a first magnet provided inside the buckle and which moves in correspondence with the engagement of the buckle and the stopper mechanism of the buckle; a second magnet provided and secured inside the buckle; first and second magnetic sensors provided inside the buckle and arranged such that they detect the intensity of the magnetic field of the first magnet and the second magnet, become outputs that mutually and complementarily change during the engagement
on-engagement of the tongue plate, and generate outputs mutually contracting with each other even in the respective engagement states; and a judgment unit for judging the engagement
on-engagement of the tongue plate and the buckle from the respective outputs of the first and second magnetic sensors. The first and secondmagnetic sensors are, for example, a hall IC, or MR IC.
The present invention is a seatbelt device for securing a passenger to a seat with a webbing, comprising: a buckle capable of freely engaging with a tongue plate mounted on the webbing; a coil spring provided inside the buckle and which expands and contracts in correspondence with the engagement with the tongue plate; an inductance detector for obtaining the output corresponding to the inductance of the coil spring; and
a judgment unit for judging that a webbing has been fastened when the output of the inductance detector is within a prescribed range.
Preferably, the judgment unit judges that a webbing has been fastened when the output of the inductance detector is within a first range, that a webbing has not been fastened when the output is within a second range, and that there is a malfunction when the output is wi

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