Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1998-10-29
2001-04-03
Hofsass, Jeffery (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S667000, C340S668000, C340S438000, C340S457100, C340S439000, C340S461000, C280S807000, C280S808000, C280S806000, C280S801100
Reexamination Certificate
active
06211793
ABSTRACT:
The present invention relates to a sensor for sensing the load applied to a vehicle safety belt and a vehicle safety belt apparatus incorporating such a sensor.
Vehicle safety belts are used in most passenger vehicles for restraining vehicle occupants and/or cargo in position in the event of hard braking or an accident. In most countries, wearing of safety belts is compulsory and most passenger vehicles are fitted with safety belts for each seat.
It is an object of the present invention to provide a sensor for sensing the load applied to vehicle safety belts.
According to one aspect of the invention there is provided a load sensor for sensing the load applied to a vehicle safety belt comprising means for determining an electrical characteristic of the belt, which characteristic is affected by loads applied to the belt and means for comparing the sensed electrical characteristic with a reference level for the characteristic.
According to another aspect of the invention, there is provided a vehicle safety belt load sensor comprising means for determining an electrical characteristic of a belt which characteristic is affected by load applied to the belt and means for comparing the sensed characteristic with a reference level.
The means for comparing the sensed characteristic with the reference level preferably comprises means for determining whether the sensed characteristic falls within a predetermined range. The sensor preferably includes means for indicating when the sensed characteristic falls outside the predetermined range.
In that way, the sensor can indicate when an excessive load has been applied to the safety belt which requires replacement of the safety belt.
The electrical characteristic of the belt may be the electrical resistance or capacitance of the belt. Alternatively, the sensor may measure the potential difference across the belt or the sensor may measure a current applied across the belt.
The sensor is preferably mounted on the belt.
According to a further aspect of the invention, there is provided a vehicle safety belt apparatus including a safety belt, a load sensor for sensing load applied to the safety belt, the sensor comprising means for determining an electrical characteristic of the belt which is affected by load applied to the belt and means for comparing the sensed characteristic with a reference level.
Preferably the means for comparing the sensor characteristic with a reference level determines whether the characteristic falls within a predetermined range.
The means for determining the electrical characteristic of the belt may comprise first and second electrical contacts on the belt, electrically connected to electrical characteristic sensing means. The first contact is preferably arranged at one end of the belt and the second contact is preferably arranged at the other end of the belt. Alternatively, where one end of the seat belt is wound on to an inertia reel and passes over a bracket above the passenger's shoulder and the other end is secured elsewhere in the vehicle, the first contact may comprise a brush contact at the mouth of the inertia reel and the second contact may comprise a contact on the aforesaid other end. In such a case, means may be provided on the inertia reel to determine the length of belt that has been pulled from the inertia reel.
Calibration means may be provided for calibrating the reference level or reference range of the electrical characteristic of the belt. Such calibration may be conducted on installation of the belt within a vehicle. Alternatively, where the brush contacts described above are used, the calibration means may calibrate the reference level of the belt each time the belt is worn by a passenger. In such a case, the calibration means may be actuated by insertion of the seat belt tongue into the catch of the seat belt anchor.
In a preferred embodiment, the seat belt includes conductive fibres which preferably extend the full length of the belt. The fibres may be interwoven with the belt webbing. The fibres may be metallic fibres or carbon fibres. Where conductive fibres are provided as part of the belt, the measured electrical characteristic will be one of electrical resistance, potential difference or current. The fibres may be arranged to break at a predetermined belt loading. In that case, the electrical continuity of the fibres will be broken and the sensor can then indicate that the belt should be replaced.
In one embodiment, conductive fibres may be provided at each edge of the belt and across one end of the belt so as to connect the fibres at each edge. In that case, the first and second contacts could be provided at the opposite end of the belt, one at each edge thereof.
As mentioned above, the apparatus may include means for indicating that the electrical characteristic falls outside a predetermined range. Preferably, the apparatus includes means to indicate that the belt has experienced an excessive load. That means may include circuitry to indicate to the driver of the vehicle that one of the belts in the vehicle has been excessively loaded and the indicating means may include a display on the instrument panel of the vehicle. Preferably, the display indicates which belt is affected.
The apparatus may include means to prevent ignition of this vehicle engine in the event that a safety belt has previously been excessively loaded. The apparatus may include means to indicate to the engine immobilizer that ignition of the engine should be prevented.
The safety belt may be a safety belt for a vehicle occupant or a restraining belt for cargo in a vehicle.
REFERENCES:
patent: 5181739 (1993-01-01), Bauer et al.
patent: 5184845 (1993-02-01), Omura
patent: 5544918 (1996-08-01), Fleming et al.
patent: 5764139 (1998-06-01), Nojima et al.
patent: 5770997 (1998-06-01), Kleinberg et al.
Breed Automotive Technology Inc.
Drayer Lonnie
Hofsass Jeffery
Nguyen Hung
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