Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
1998-10-26
2001-03-20
Allen, Stephone B. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C250S227140, C250S559400, C355S117000, C318S480000
Reexamination Certificate
active
06204497
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an air bag deployment trigger sensor, and in particular, to a device for triggering the deployment of an air bag within a vehicle after an impact resulting from a collision.
BACKGROUND OF THE INVENTION
The response time from an impact to initial air bag deployment is extremely important for minimizing injury to one or more occupants in a vehicle which is involved in a collision. Every microsecond or millisecond saved between impact and deployment of a vehicle's air bag will substantially reduce injury in the event of an accident. As such a fast and effective air bag deployment trigger within the vehicle is essential.
Past air bag triggering devices have utilized a mechanical safing sensor also known as an inertial ball. These sensors typically include a ball and magnet arrangement in which an impact causes the separation of the ball from the magnet which in turn makes contact with two electrodes and triggers a sensor circuit leading to activation of an air bag deployment system in the vehicle. Air bag deployment is dependent upon the response time speed of its sensor and triggering device. The conventional safing sensors or mechanical triggering devices for air bag deployment have a relatively slow response time. Additionally, if more than one safing sensor or mechanical triggering device is disposed within a vehicle, all the air bags within vehicle will be deployed simultaneously. Furthermore, the ball and magnet system is large and bulky and its size prevents its placement in certain areas of a vehicle such as within a bumper. Also, the ball and magnet triggering system must be strategically placed within the vehicle in order to achieve the appropriate response upon impact. The ball and magnet triggering system may also be ineffective in certain circumstances since the ball and magnet may sometimes dislodge inappropriately thereby rendering the device prone to false deployments. For example, under some conditions, mechanical sensors may be prone to trigger by, among other things, driving over bumpy roads, banging on the vehicle, or upon slight impacts and incidental bumps directed upon the vehicle but which are below a threshold required for air bag deployment. As a result of false deployments, a vehicle owner would be forced to expend money to repack the falsely deployed air bag or to have a new one installed.
A system has recently been proposed in U.S. Pat. No. 5,335,749 to Taguchi et al. which provides an air bag triggering device having a flexible fiber optic rod arranged inside a cylindrical beam positioned within the space inside the side door of an automobile. A flexible material is also arranged inside the cylindrical beam which occupies the space between the cylindrical beam and the fiber optic. The fiber optic is connected to a light receiving portion on one end of the cylindrical beam and to a light emitting portion on the other end. In this construction, a lateral impact force to the side of the door causes a lateral deformity in the fiber optic which results in a difference in the amount of light received at the light receiving end, generally a reduced amount of light. As a result of the deformity of the fiber optic and the reduced receipt of light by the receiving end, the air bag trigger is activated resulting in inflation of the vehicle's air bag.
However, the flexible nature of the fiber optic may cause false activation of the trigger which would result in false deployment of the air bag. For example, random changes in the amount of light received at the light receiving end of a flexible fiber may cause air bag deployment. Other events such as a minor indentations in the vehicle door caused by a person leaning against the door, or driving the vehicle over a bumpy road may cause a deformity or shift the fiber optic hence causing a change in the light received by the light receiving end and causing the air bag to be falsely deployed.
Accordingly, there is a need for an air bag triggering device which is relatively compact for placement anywhere within a vehicle, which decreases deployment time for inflation of an air bag upon impact, which can be placed in a particular critical crash zone of a vehicle, and which eliminates the prevalence of false deployments inherent in the prior art.
OBJECTS AND SUMMARY OF THE INVENTION
It is thus a general object of the present invention to provide an optical device for triggering the deployment of a vehicle air bag which overcomes the disadvantages of the prior art.
A more specific object of the present invention is to provide an air bag deployment trigger sensor for placement within a vehicle and which includes an emitter, a detector, and a waveguide positioned between the emitter and the detector and across which optical rays are transmitted.
It is a further object of this invention to provide an air bag deployment trigger sensor in which an emitter transmits continuous, pulsed or encoded optical rays or signals across a rigid waveguide to be received by a detector and measured, compared, or decoded by a sensor circuit.
It is an additional object of this invention to provide an air bag deployment trigger sensor in which the breakage of a rigid waveguide as a result of an impact interrupts the transmission of light across the waveguide and in turn triggers the deployment of an air bag within the vehicle.
According to the present invention, an emitter and a detector are positioned on opposite ends of a rigid waveguide. The rigid waveguide, which is of a predetermined tensile strength, transmits the emitted optical rays from the emitter to the detector to which a sensor circuit is attached for measuring, comparing or decoding the received rays. Any direct impact which reaches or exceeds a predetermined threshold causes the waveguide to break. Breakage of the waveguide interrupts or alters the optical signal to the detector and causes a termination or differential in the signal received by the detector. When the sensor circuit detects this termination or differential signal, it triggers the deployment of the vehicle's air bag.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for the purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.
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“Advances In Airbag Materials Keep Market Exploding”Inside Automot
Schiller Chantal
Schiller Norman
Allen Stephone B.
Sofer & Haroun, LLP.
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