| 摘要 |
A sensing device which determines the direction of an impact includes an inertia member 8, a housing 10 accommodating the inertia member therein and at least three impact sensors 50 disposed in such a manner as to be in contact with an outer peripheral surface of the inertia member, each impact sensor comprising a piezoelectric element 1 for generating a voltage having amplitude corresponding to an applied stress and a member 5 of synthetic rubber urging the piezoelectric sensor against the inertia member. The inertia member 8 is supported vertically in the housing by springs 9 and has projections 8A which engage grooves 4b in the end of the impact sensors 50. There are preferably six impact sensors 50 arranged symmetrically around the inertia member. Each sensing member is connected to a bistable circuit. On an impact, particularly a car crash, the outputs of all sensors that reach a predetermined value will set the associated bistable circuit and the results can be stored in RAM and used to trigger inflation of an appropriate air-bag depending on the direction of impact. <IMAGE> |
