Temperature-compensating accelerometer
First Claim
1. An accelerometer comprisinga housing having a passage extending therein:
- stop means defining a first end of the passage, said stop means moving longitudinally of the passage in response to temperature;
a magnetically-permeable element secured to said housing proximate with the passage;
a magnetic sensing mass in the passage, said sensing mass being magnetically biased towards said magnetically-permeable element so as to remain in a first position against the stop means until said magnetic bias is overcome by acceleration of said housing, whereupon said sensing mass is displaced in response to such acceleration from said first position towards a second position in the passage, said magnetic bias being sufficient to return said sensing mass to said first position from any other position in the passage short of said second position; and
switch means operable by said sensing mass when said sensing mass is displaced to said second position.
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Accused Products
Abstract
An acceleration sensor comprises a tube formed of an electrically-conductive non-magnetic material; a stop defining an end of the tube which moves longitudinally thereof in response to temperature; a magnetically-permeable element, such as a iron washer, proximate with the end of the tube; and a sensing mass in the tube comprising a pair of permanent magnets secured to the opposite sides of an iron spacer so as to place a pair of like magnetic poles thereof in opposition. In operation, the sensing mass interacts with the iron washer so as to be magnetically biased against the stop, while the stop moves longitudinally of the tube to maintain a nearly constant threshold magnetic bias on the sensing mass irrespective of variations in sensor temperature. The sensing mass is displaced in response to acceleration of the housing from its first position against the stop towards a second position in the tube when such acceleration overcomes the magnetic bias, while the tube itself interacts with the sensing mass to provide magnetic damping therefor. Upon reaching the second position in the tube, the sensing mass bridges a pair of electrical contacts with an electrically-conductive surface thereof to indicate that a threshold level of acceleration has been achieved. An electrical coil is secured proximate with the iron washer which, when energized, reversibly magnetizes the latter, whereby the sensing mass is either repelled to the second position in the tube or more strongly biased against the stop.
17 Citations
16 Claims
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1. An accelerometer comprising
a housing having a passage extending therein: -
stop means defining a first end of the passage, said stop means moving longitudinally of the passage in response to temperature; a magnetically-permeable element secured to said housing proximate with the passage; a magnetic sensing mass in the passage, said sensing mass being magnetically biased towards said magnetically-permeable element so as to remain in a first position against the stop means until said magnetic bias is overcome by acceleration of said housing, whereupon said sensing mass is displaced in response to such acceleration from said first position towards a second position in the passage, said magnetic bias being sufficient to return said sensing mass to said first position from any other position in the passage short of said second position; and switch means operable by said sensing mass when said sensing mass is displaced to said second position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An accelerometer comprising
a tube; -
stop means defining an end of said tube, said stop means moving longitudinally of said tube in response to temperature; a magnetically-permeable element proximate with said tube; a magnetic sensing mass in said tube, said sensing mass being magnetically biased towards said magnetically-permeable element so as to remain in a first position against said stop means until said magnetic bias is overcome by acceleration of said tube, whereupon said sensing mass is displaced in response to such acceleration from said first position towards a second position in said tube, said magnetic bias being sufficient to return said sensing mass to said first position from any other position in said tube short of said second position; and switch means operable by said sensing mass when said sensing mass is displaced to said second position. - View Dependent Claims (14, 15, 16)
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Specification