Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
238 words
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.
Claim 2
Dependent Claim
238 words
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.
Claim 3
Dependent Claim
31 words
An arrangement according to claim 1 wherein the first algorithm is adapted to distinguish a crash of at least a predetermined severity from a crash of less than the predetermined severity.
Claim 4
Dependent Claim
28 words
An arrangement according to claim 1 wherein the second algorithm is adapted to distinguish a crash of any severity from an error signal originating in the crash sensor.
Claim 5
Dependent Claim
20 words
An arrangement according to claim 1 wherein the crash sensor is an accelerometer providing a signal representative of sensed acceleration.
Claim 6
Dependent Claim
25 words
An arrangement according to claim 1 wherein the signal from the crash sensor only contains frequencies below a predetermined frequency in the range 300-400 Hz.
Claim 7
Dependent Claim
23 words
An arrangement according to claim 1 wherein the said first algorithm comprises the step of integrating the said signal from the crash sensor.
Claim 8
Dependent Claim
13 words
An arrangement according to claim 1 wherein the said predetermined number comprises four.
Claim 9
Dependent Claim
14 words
An arrangement according to claim 1 wherein the high-pass filter comprises an analogue filter.
Claim 10
Dependent Claim
23 words
An arrangement according to claim 1 wherein the filter is adapted to pass frequencies above a selected frequency in the range 50-150 Hz.
Claim 11
Dependent Claim
13 words
An arrangement according to claim 9 wherein the selected frequency is 100 Hz.
Claim 12
Dependent Claim
18 words
An arrangement according to claim 1, wherein the said threshold levels are spaced above and below the origin.
Claim 13
Dependent Claim
37 words
An arrangement according to claim 1 wherein the said second switch is responsive also to an additional signal, both the said second output signal and the said additional signal being present before the switch is rendered conductive.
Claim 14
Dependent Claim
40 words
An arrangement according to claim 12 wherein the said additional signal is derived from the accelerometer by filtering the output of the accelerometer through a high-pass filter and determining that the output of the high-pass filter exceeds a predetermined threshold.
Claim 15
Dependent Claim
23 words
An arrangement according to claim 13 wherein the said predetermined threshold is equivalent to a sensed acceleration in the range of 3-6 G.
Claim 16
Dependent Claim
20 words
An arrangement according to claim 14 wherein the said predetermined threshold is equivalent to a sensed acceleration of 4 G.
Claim 17
Dependent Claim
28 words
An arrangement according to claim 1 wherein the processing means which process the said signal comprises a micro-processor operating at a sampling frequency of at least 1,500 Hz.
Claim 18
Dependent Claim
13 words
An arrangement according to claim 16 wherein the sampling frequency is 2,000 Hz.
Claim 19
Dependent Claim
29 words
An arrangement according to claim 1 wherein the processing means which process the said further signal comprises a micro-processor operating at a sampling frequency of at least 1,500 Hz.
Claim 20
Dependent Claim
13 words
An arrangement according to claim 18 wherein the sampling frequency is 2,000 Hz.
Claim 21
Dependent Claim
12 words
An arrangement according to claim 1 adapted to sense a side impact.