Abstract: An acceleration sensor comprises a tube formed of an electrically-conductive, nonmagnetic material; an annular magnetically-permeable element, such as an iron washer, encircling a longitudinal portion of the tube; a magnetic sensing mass in the tube which magnetically interacts with the washer so as to be magnetically biased towards a first or "rest" position in the tube characterized in that a longitudinal portion of the sensing mass is situated within the portion of the tube encircled by the washer, the sensing mass being displaced from its rest position in the tube towards a second position therein in response to an accelerating force exceeding the magnetic bias thereon; and a switch operated by the sensing mass when the sensing mass is displaced to its second position in the tube.

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.