Apparatus for triggering a passive safety device
First Claim
1. An apparatus for triggering a passive safety device in a vehicle in response to an impact, comprising at least two individual acceleration sensors (2, 3), each individual acceleration sensor having its own sensitivity axis (A2, A3) oriented differently than a respective sensitivity axis of the other individual acceleration sensor so that each sensor covers its own angular sensitivity range to discriminate between different impact directions, one signal evaluating and processing channel (5, 6) connected to each individual acceleration sensor (2, 3) respectively, each signal evaluating and processing channel comprising first signal recognizing circuit means (7, 8, 9) for determining the magnitude of an impact and second circuit means (10, 11, 12) for determining an impact duration, said first and second circuit means being connected to an output of the respective individual acceleration sensor (2, 3), and threshold circuit means (41, 41'"'"', 51, 51'"'"') connected to an output of a respective one of said signal recognizing circuit means, whereby each individual acceleration sensor (2, 3) is part of a respective series circuit with its own signal recognizing circuit means and with its own threshold circuit means for forming said signal evaluating and processing channels, to distinguish types of impacts from each other, and logic trigger circuit means (81, 82, 83) connected to said series circuit channels for triggering said passive safety device, each of said signal evaluating and processing channels comprising further threshold circuit means (13, 13'"'"';
- 21, 21'"'"') comprising at least two threshold switches, each threshold switch having a different threshold value for enabling a triggering of said passive safety device in response to a signal exceeding the respective threshold value, said signal evaluating and processing channels further comprising means (34, 37,
74) for discriminating minor impacts and generating respective blocking signals and triggering signals (81, 82,
83) for the operation of said passive safety device (15) in response to signals from said signal evaluating and processing channels, said trigger circuit means comprising logic circuit means having first inputs connected to all threshold switches and further inputs connected to each signal recognizing circuit means, said logic circuit means having AND-gates and OR-gates interconnected to provide a circuit characteristic that passes signals only from certain threshold switches in response to said blocking signals and said triggering signals for triggering said passive safety device in response to one impact signal while suppressing other impact signals to avoid such triggering of said safety device in response to said other impact signals.
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Accused Products
Abstract
A crash sensor is constructed for triggering a passive safety device, such as an air bag or a seat belt tightening device. The crash sensor is capable to distinguish between different types of impacts such as front impacts, rear impacts, side impacts, and minor impacts, for example occurring in a repair shop. For example, the air bag shall be deployed only in response to a frontal impact. The crash sensor has at leasst two acceleration sensors having sensitivity axes arranged at different angles relative to the longitudinal vehicle axis or travel direction. The output signals of the acceleration sensors are integrated in respective integrated circuits and supplied to a threshold value circuit which in turn provides the necessary signal for activating a trigger circuit. Each signal processing channel is equipped with at least two parallel threshold value switches which cooperate with signal validating or signal recognizing circuits to distinguish between different impacts for permitting the deployment or for preventing the deployment of the safety device. The trigger circuit itself is also a logic circuit in which the individual inputs are received through input conductors carrying signals representing the various criteria for the deployment or prevention of the deployment of the safety device. Thus, the safety device is deployed only if a frontal impact has been recognized.
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Citations
18 Claims
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1. An apparatus for triggering a passive safety device in a vehicle in response to an impact, comprising at least two individual acceleration sensors (2, 3), each individual acceleration sensor having its own sensitivity axis (A2, A3) oriented differently than a respective sensitivity axis of the other individual acceleration sensor so that each sensor covers its own angular sensitivity range to discriminate between different impact directions, one signal evaluating and processing channel (5, 6) connected to each individual acceleration sensor (2, 3) respectively, each signal evaluating and processing channel comprising first signal recognizing circuit means (7, 8, 9) for determining the magnitude of an impact and second circuit means (10, 11, 12) for determining an impact duration, said first and second circuit means being connected to an output of the respective individual acceleration sensor (2, 3), and threshold circuit means (41, 41'"'"', 51, 51'"'"') connected to an output of a respective one of said signal recognizing circuit means, whereby each individual acceleration sensor (2, 3) is part of a respective series circuit with its own signal recognizing circuit means and with its own threshold circuit means for forming said signal evaluating and processing channels, to distinguish types of impacts from each other, and logic trigger circuit means (81, 82, 83) connected to said series circuit channels for triggering said passive safety device, each of said signal evaluating and processing channels comprising further threshold circuit means (13, 13'"'"';
- 21, 21'"'"') comprising at least two threshold switches, each threshold switch having a different threshold value for enabling a triggering of said passive safety device in response to a signal exceeding the respective threshold value, said signal evaluating and processing channels further comprising means (34, 37,
74) for discriminating minor impacts and generating respective blocking signals and triggering signals (81, 82,
83) for the operation of said passive safety device (15) in response to signals from said signal evaluating and processing channels, said trigger circuit means comprising logic circuit means having first inputs connected to all threshold switches and further inputs connected to each signal recognizing circuit means, said logic circuit means having AND-gates and OR-gates interconnected to provide a circuit characteristic that passes signals only from certain threshold switches in response to said blocking signals and said triggering signals for triggering said passive safety device in response to one impact signal while suppressing other impact signals to avoid such triggering of said safety device in response to said other impact signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
- 21, 21'"'"') comprising at least two threshold switches, each threshold switch having a different threshold value for enabling a triggering of said passive safety device in response to a signal exceeding the respective threshold value, said signal evaluating and processing channels further comprising means (34, 37,
Specification