Crash detector arrangement
First Claim
1. A crash detector arrangement adapted to activate a safety device, the arrangement comprising a power supply connected to a series connection of a first switch, an actuator for activating the safety device and a second switch, the arrangement further comprising a crash sensor providing a signal, processing means adapted to process the said signal in accordance with a first predetermined algorithm to provide a first output signal to render the first switch conductive, and processing means adapted to process a further signal from the crash sensor in accordance with a second algorithm to provide a second output signal to render the second switch conductive, the two algorithms being different, the further signal being derived by passing the output of the crash sensor through a high-pass filter, each algorithm being adapted to distinguish a signal from the crash sensor due to a crash having predetermined characteristics from a signal from the crash sensor due to other causes, so that the first output signal and the second output signal are each provided in response to a crash having said predetermined characteristics, said processing means being adapted to process the further signal and comprising means to determine the number of times the output of the high-pass filter passes predetermined threshold levels in a predetermined period of time and, in response to the number of passings exceeding a predetermined number, to provide said second output signal to render the second switch conductive.
3 Assignments
0 Petitions
Accused Products
Abstract
A crash detector arrangement comprises a crash sensor(1) in the form of an accelerometer which provides a signal to a micro-processor(2) which uses a first algorithm to determine if the signal is representative of a crash of a predetermined severity and which consequently provides an output(8) rendering a first switch(9) conductive. The output of the accelerometer(1) is provided also to the micro-processor(2) through a high pass filter. This input to the micro-processor is processed by another, different, algorithm determined to differentiate a crash from a signal error in the accelerometer. A second output(7) is generated by the micro-processor which is used to assist in the control of a further switch(13). The two switches(9,13) are in a series connection incorporating a source of power(10) and a resistor(12). When current passes through the resistor, the safety device is activated. The second output(7) of the micro-processor(2) passes through an AND-gate(6) which also receives an input from a threshold detector(4) and from a check circuit(14).
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Citations
20 Claims
- 1. A crash detector arrangement adapted to activate a safety device, the arrangement comprising a power supply connected to a series connection of a first switch, an actuator for activating the safety device and a second switch, the arrangement further comprising a crash sensor providing a signal, processing means adapted to process the said signal in accordance with a first predetermined algorithm to provide a first output signal to render the first switch conductive, and processing means adapted to process a further signal from the crash sensor in accordance with a second algorithm to provide a second output signal to render the second switch conductive, the two algorithms being different, the further signal being derived by passing the output of the crash sensor through a high-pass filter, each algorithm being adapted to distinguish a signal from the crash sensor due to a crash having predetermined characteristics from a signal from the crash sensor due to other causes, so that the first output signal and the second output signal are each provided in response to a crash having said predetermined characteristics, said processing means being adapted to process the further signal and comprising means to determine the number of times the output of the high-pass filter passes predetermined threshold levels in a predetermined period of time and, in response to the number of passings exceeding a predetermined number, to provide said second output signal to render the second switch conductive.
Specification